Coffea — the genus

Coffee is made from the seeds of fruits produced by plants of the genus Coffea, which belongs to the Rubiaceae family. The genus comprises many species, but Coffea arabica and Coffea canephora are the most important in international trade. After flowering, coffee plants develop fruits commonly known as coffee cherries. Most cherries contain two seeds; after processing these are sold as green coffee.

Sources: World Coffee Research – Coffee Varieties Catalog – https://varieties.worldcoffeeresearch.org/about-the-catalog/whats-included

Arabica (Coffea arabica)

Arabica is the world's most commercially important coffee species and is valued for its aromatic complexity and refinement. Botanically it is unusual: it arose through a natural hybridisation of Coffea canephora and Coffea eugenioides. A genetic study published in 2024 dated that event to approximately 350,000–610,000 years ago.

Arabica has 44 chromosomes, twice the number found in either parent species. It can self-pollinate and has relatively limited genetic diversity among widely cultivated lines. Many traditional varieties are consequently vulnerable to diseases and changes in growing conditions.

It often thrives in tropical highlands where moderate temperatures and suitable rainfall can slow the ripening of the cherries. Depending on variety, terroir and processing, its flavours may range from flowers and citrus to ripe berries, nuts, cocoa and chocolate. A lively, nuanced acidity and sweetness make Arabica especially interesting when the expression of origin matters.

Growing Arabica can require more demanding conditions and greater care. It is susceptible to certain diseases and usually commands higher green-coffee prices than Robusta. Higher prices, however, are not automatic proof of better quality; both species display considerable variation.

Arabica encompasses many varieties with different growth habits, yields, resilience and sensory potential. Much like grape varieties in wine, it is not a single flavour but a diverse family of characters.

Sources: Scalabrin et al. (2024), The genome and population genomics of allopolyploid Coffea arabica, Nature Genetics – https://doi.org/10.1038/s41588-024-01695-w; World Coffee Research – https://varieties.worldcoffeeresearch.org/

Robusta (Coffea canephora)

Robusta is the second most widely grown commercial coffee species. Originally from tropical African forests, it is now cultivated notably in Vietnam, Brazil, Indonesia and Uganda. Many Robusta cultivars tolerate higher temperatures, grow at lower altitudes and offer greater yields or resistance to certain diseases than Arabica.

Robusta usually contains substantially more caffeine, which also plays a protective role for the plant. On average, its caffeine content is about twice that of Arabica. At the same dose and with a comparable brewing method, a drink prepared entirely from Robusta will therefore normally contain more caffeine than one prepared entirely from Arabica. Studies frequently report approximately 0.8–1.5% caffeine in roasted Arabica and 1.8–2.6% in Robusta, although actual values vary with variety, sample, dose, grind and extraction.

Robusta often shows greater bitterness and body, less perceived acidity and aromas that may suggest earth, wood, nuts or chocolate. It can contribute a particularly dense and persistent crema to espresso. It has a traditional place in southern Italian espresso blends, valued for strength, texture and crema. Relatively high yields and lower production costs can also make it less expensive on the green-coffee market.

Choosing between Arabica and Robusta is therefore not merely a question of strength or crema. It depends on the intended sensory profile and the positioning of the coffee.

Sources: World Coffee Research – https://varieties.worldcoffeeresearch.org/; International Coffee Organization (market statistics and price series) – https://www.ico.org/; de Mejia & Ramirez-Mares / Review (2019), Caffeine Consumption through Coffee, Beverages 5(2), 37 – https://doi.org/10.3390/beverages5020037

Liberica and Excelsa

Beyond Arabica and Robusta, other species play smaller but intriguing roles in coffee production. Coffea liberica originated in West Africa and is distinguished by its large leaves, fruits and seeds. It is grown in parts of South-East Asia and may produce striking woody, fruity or spicy sensory notes.

Excelsa was long treated as a Liberica variety. More recent genetic research supports recognising it as a separate species, Coffea dewevrei, originally from Central Africa. It differs from Liberica in both genetic and botanical characteristics.

These species attract research interest because their adaptations to different environments may be relevant to coffee's future. They also remind us how much botanical diversity lies beyond the two dominant commercial species.

Sources: World Coffee Research – https://worldcoffeeresearch.org/; botanical taxonomy: Plants of the World Online, Kew – https://powo.science.kew.org/

Coffee varieties — the grape varieties of coffee

What a grape variety is to wine, a coffee variety is to coffee. It affects growth, yield, disease resistance and the potential flavour of the cup. Whether that potential becomes exceptional coffee also depends on climate, soil, cultivation, processing and roasting. Many widespread Arabica cultivars derive from two historic families, Typica and Bourbon, but the diversity extends from Ethiopian landraces to modern crosses selected for resilience and quality.

Typica is one of the oldest and most influential Arabica lines. It spread from Ethiopia through Yemen, India, Java and Amsterdam to the Americas. It offers considerable quality potential, but relatively low yields and susceptibility to important diseases.

Bourbon takes its name from the island of Bourbon, now Réunion, where French missionaries brought coffee from Yemen in the early eighteenth century. An ancestor of many later varieties, it can give balanced, sweet and complex cups in favourable conditions.

Caturra is a naturally occurring Bourbon mutation discovered in Brazil early in the twentieth century. Its compact growth permits closer planting and made it important in Central America and coffee breeding.

Catuaí was developed in Brazil by crossing Caturra and Mundo Novo. It combines relatively compact growth with good yield potential and is cultivated with red or yellow cherries, but remains susceptible to coffee leaf rust.

Gesha, also written Geisha, originated in Ethiopia and became internationally famous in Panama. A lot from Hacienda La Esmeralda attracted attention at Best of Panama in 2004. Floral notes of jasmine, bergamot and tea are often associated with it, but not every coffee sold as Gesha has the same genetic background.

SL28 and SL34 were selected in Kenya by the Scott Agricultural Laboratories in the 1930s. Both are associated with the reputation of fine Kenyan coffees, but are genetically distinct: SL28 is more closely related to Bourbon and SL34 to Typica.

Ethiopian landraces comprise exceptionally diverse indigenous Arabica populations. Commercial descriptions such as “heirloom” cover numerous different genetic origins, offering great sensory diversity and important resources for future breeding.

The Timor Hybrid emerged as a natural Arabica–Robusta hybrid on Timor in the twentieth century. Its resistance traits proved important in developing coffee leaf-rust-resistant lines, including the Catimor family after crosses with Caturra. Resilience and good cup quality need not be opposites.

Sources: World Coffee Research, Arabica Varieties Catalog – https://varieties.worldcoffeeresearch.org/arabica/varieties; Hacienda La Esmeralda, variety history – https://haciendaesmeralda.com/our-story/

Altitude, climate and bean density

“High-grown coffee” describes more than a place on a map. Temperature often falls with altitude, and, under appropriate conditions, coffee cherries may ripen more slowly. This can influence the development, physical density and chemical composition of the seeds and ultimately their aromatic potential.

Yet there is no mechanical rule linking a greater altitude to a better cup. Variety, rainfall, sunlight, nutrition, processing and the wider climate matter too. A high elevation guarantees neither dense beans nor excellent flavour, and exceptional coffee can come from lower elevations.

Some producing countries use trade terms such as “Hard Bean” or “Strictly Hard Bean”, based on regional altitude categories. They are not substitutes for an actual density measurement or a sensory assessment.

Latitude is also crucial: conditions encountered at high elevation near the equator may occur lower down farther from it. What matters is the combination of temperature, climate and plant development, not metres above sea level alone.

Sources: Sarzynski et al. (2023), Genetic–environment interactions and climatic variables effect on bean physical characteristics and chemical composition of Coffea arabica, Journal of the Science of Food and Agriculture – https://doi.org/10.1002/jsfa.12544; Shade and Altitude Implications on the Physical and Chemical Attributes of Green Coffee Beans from Gorongosa Mountain, Mozambique (2022), Agronomy – https://doi.org/10.3390/agronomy12102540

Terroir

The term “terroir” comes from wine and describes how a place's natural conditions and human decisions together shape an agricultural product. With coffee, it prompts a compelling question: how much of the cup expresses the place where its cherries developed?

An origin encompasses much more than a country or an altitude. Temperatures, rainfall, soil structure, slope and shade affect growth. Variety, harvesting and post-harvest processing add further layers. These factors can jointly influence a bean's chemistry and its sensory properties.

Simple taste formulas are misleading. Volcanic soil does not automatically create a particular acidity, and two coffees from the same region may taste completely different. Roasting and brewing further determine which traits become perceptible. Meaningful comparisons therefore require as similar a roast and preparation as possible.

Terroir is neither a flavour note nor a quality guarantee. It is a way of understanding coffee as an agricultural product shaped by a particular place and by the people working there.

Sources: Scholz et al. (2018), The typicity of coffees from different terroirs, Food Research International – https://doi.org/10.1016/j.foodres.2018.07.058; Williams et al. (2022), Does Coffee Have Terroir and How Should It Be Assessed?, Foods – https://doi.org/10.3390/foods11131907

Growing systems — full sun, partial shade and agroforestry

Coffee can be cultivated very differently even on neighbouring farms. Beyond altitude and climate, growers must consider topography, light, trees, soil, water and the plants themselves. “Full sun”, “semi-shade” and “agroforestry” are not strictly separate categories: the first two mainly describe light exposure, whereas agroforestry describes the deliberate integration of coffee with trees and other woody plants. An agroforestry system may itself provide relatively little shade.

Topography — the site comes first

Slope, aspect, altitude, drainage, access and the risk of erosion influence where and how a plantation can be established. Steep, uneven ground may favour manual cultivation and contour planting rather than mechanisation. Exposure to the sun, prevailing winds and water movement can create very different microclimates even within a single farm. Suitable growing systems are therefore chosen for the terrain, not imposed regardless of it.

Beyond altitude, the orientation of a slope also affects the daily distribution of sunlight, wind exposure and the likelihood of heat stress. Upper and lower slopes may have distinct water availability and erosion patterns. On steep ground, access for harvesting, transport and maintenance can become as important as the biological suitability of the site. Ground cover and planting along contours may help limit soil loss, but the appropriate measures need to be adapted to the local terrain.

Full sun — coffee in open fields

Coffee grows with little or no overhead canopy. Ordered rows may ease management and, on suitable land, mechanised operations. With sufficient water, nutrition and good farming practices, yields can be high. Plants and soil are more exposed to direct sun, heat and wind, which may raise water requirements. Full-sun cultivation does not automatically imply pesticide use, just as shade-grown coffee is not automatically organic.

Semi-shade — regulating light

Coffee plants grow beneath scattered shade trees or an open canopy. Trees may moderate high temperatures and intense radiation while still allowing sufficient light for photosynthesis and fruit production. The appropriate amount of shade depends on variety, temperature, water availability and planting density. In some conditions moderately shaded systems yield as much as full-sun plantations; there is no universally optimal shade percentage.

Agroforestry — coffee within a wider ecosystem

Agroforestry deliberately combines coffee with trees and sometimes other crops. Simple arrangements use few shade-tree species; complex systems may include tall trees, smaller fruit trees and coffee beneath several canopy layers. Trees can provide fruit, timber or other products, contribute leaf litter to soil cover and offer habitats for wildlife. A diverse agroforestry landscape is ecologically different from a plantation shaded by one tree species.

Managing diversity requires care. Canopies may need pruning to provide adequate light. Depending on species and spacing, trees may compete with coffee for water and nutrients, and dense vegetation can complicate work and harvesting. A humid microclimate may favour some diseases. Success therefore depends on selecting and arranging plants for the specific site.

Can fruit and shade trees affect flavour?

Tree species can influence coffee indirectly through shade density, temperature, moisture, soil biology, organic matter and the pace of fruit ripening. Research has found changes in bean chemistry or sensory characteristics under certain tree species, but results are not consistent across studies and sites. Fruit growing beside a coffee tree does not simply transfer its own flavour to the beans: mango trees, for instance, do not automatically produce mango-flavoured coffee.

Different shade-tree species may also behave differently over the seasons: their crowns, leaf litter and root systems influence radiation, the water balance and competition for nutrients. Studies do not demonstrate a universal flavour associated with a particular fruit tree. Comparisons must therefore distinguish effects on measured bean chemistry from effects that trained tasters can actually identify in the cup.

Yields, quality and environmental outcomes — no simple ranking

More shade does not necessarily mean a better cup; full sun does not mean a poor one. Sensory quality depends on genetics, climate, maturity, nutrients and processing. A meta-analysis covering 142 studies found that moderate shade sometimes produced yields comparable with full sun, whereas denser shade could lower yields. Other analyses show that individual Arabica varieties respond differently to shade. For biodiversity, the number and structure of tree species and their links with natural habitats are especially important.

Organic and biodynamic are different questions

Light exposure alone does not show whether a farm is conventionally, organically or biodynamically managed. These terms concern farming inputs, soil care and specific cultivation rules; certification of any farm or lot requires valid documentation. The objective is not to choose the simplest label but to adapt plants, site, light, soil and management to one another.

Sources: Mokondoko, Ávila-Foucat & Galeana-Pizaña (2022), meta-analysis of yields and ecosystem services, Agriculture, Ecosystems & Environment – https://doi.org/10.1016/j.agee.2022.108024; Koutouleas et al. (2022), comparison of Arabica varieties under differing shade levels, Agronomy for Sustainable Development – https://doi.org/10.1007/s13593-022-00788-2; Manson et al. (2024), meta-analysis on shade and biodiversity – https://doi.org/10.1016/j.scitotenv.2024.169882; Assis Silva et al. (2018), influence of climate, topography and terrain position on coffee quality – https://doi.org/10.9734/JEAI/2018/41499; Xu et al. (2022), Impact of agro-forestry systems on the aroma generation of coffee beans, Frontiers in Nutrition – https://doi.org/10.3389/fnut.2022.968783; Getachew et al. (2023), Effects of shade tree species on soil biogeochemistry and coffee bean quality – https://doi.org/10.1016/j.agee.2023.108354

Shade cultivation and agroforestry

The ecological functions of a coffee plantation depend not only on the amount of shade but on the variety and structure of its trees. One shade tree above uniform rows creates different habitats from a multi-layered agroforestry plot with numerous species connected to nearby woodland. The preceding article explains the differences between full sun, semi-shade and agroforestry.

Arabica originated in Ethiopia's forest environments. Shade trees may temper heat extremes, protect the soil and contribute organic matter through fallen leaves. They can provide habitats for birds, insects and other organisms and, depending on their species, also yield fruits, timber or other useful products.

Shade is not an automatic promise of high cup quality. According to site, variety and canopy, it can benefit, have little effect on or harm yield, ripening and disease pressure. The goal is carefully designed cultivation rather than the greatest possible shade.

Sources: meta-analysis of cultivation and ecosystem services, Agriculture, Ecosystems & Environment (2022) – https://doi.org/10.1016/j.agee.2022.108024; meta-analysis of variety responses to shade – https://doi.org/10.1007/s13593-022-00788-2; Finca Mariposa, farm data: https://www.larbreacafe.com/pages/finca-mariposa-la-ferme-de-larbre-a-cafe

Diseases and pests of coffee plants

Coffee leaves, cherries, roots and vascular tissues can be affected by different pathogens and pests. The principal threats vary with climate, species, variety and farming methods.

Coffee leaf rust, caused by Hemileia vastatrix, produces yellow-orange spore deposits on leaves. Severe infection leads to defoliation and can reduce yields. Breeding for resistance is essential, although resistance can be overcome over time.

Coffee berry disease, particularly important in parts of Africa, is associated with Colletotrichum kahawae. It attacks mostly immature cherries, causing dark lesions and sometimes severe fruit losses. Diagnosis must distinguish it from other kinds of fruit damage.

Coffee wilt disease, caused by Fusarium xylarioides, affects the plant's water-conducting tissues; branches or entire trees may wilt and die. Root diseases due to other fungi and plant-parasitic nematodes, including Meloidogyne species, can disrupt water and nutrient uptake.

The coffee berry borer, Hypothenemus hampei, is an insect rather than a fungus. Females bore into coffee cherries and their offspring can damage the seeds. Other insects and mites matter in particular regions.

No single intervention solves all these problems. Selecting suitable varieties, maintaining hygiene during harvest and in the field, monitoring symptoms and pests, protecting soil function and adapting cultivation to the location are complementary strategies.

Sources: American Phytopathological Society – Diseases of Coffee: https://www.apsnet.org/edcenter/resources/commonnames/Pages/Coffee.aspx; CABI Compendium, Coffee Berry Disease (2026): https://doi.org/10.1079/cabicompendium.14916; World Coffee Research, varieties and disease resistance: https://varieties.worldcoffeeresearch.org/

Coffee and climate change

Coffee is sensitive to shifts in temperature, rainfall and extreme weather. Arabica in particular is adapted to specific climatic conditions. Longer heatwaves, changing rainy seasons and exceptional drought can affect growth, yield and quality.

Models suggest that areas suitable for coffee cultivation could shift considerably during this century. These are scenarios, not precise predictions for any farm: they depend on emissions pathways, local climate and modelling assumptions.

Adaptation may include choosing more suitable varieties, improving water and soil management and, where appropriate, introducing shade trees. No measure works identically everywhere. The future of coffee will depend on how successfully individual growing systems adapt to their circumstances.

Sources: World Coffee Research / CIAT, climatic suitability of Arabica regions: https://worldcoffeeresearch.org/resources/multiclass-classification-of-agro-ecological-zones-for-arabica-coffee; World Coffee Research, international variety trials: https://doi.org/10.3389/fpls.2025.1583595

The coffee cherry — anatomy of a fruit

A coffee bean is botanically a seed rather than a true bean. Depending on variety, ripe coffee cherries are usually red or yellow. Beneath the skin is pulp and a sugary, sticky layer called mucilage. A parchment-like shell and a thin silver skin protect the seed.

Most cherries hold two seeds, with their flat sides facing each other. Occasionally only one develops, producing a more rounded peaberry. Its shape alone is not evidence of better cup quality.

The fruit's layers are central to processing: removing the skin, pulp and mucilage at different stages changes the conditions for fermentation and drying. This small fruit is thus the starting point for many of the flavours associated with different coffees.

Sources: World Coffee Research, Coffee Varieties Catalog: https://varieties.worldcoffeeresearch.org/; International Coffee Organization, Coffee Botany: https://www.ico.org/

Harvesting coffee

Green, ripe and overripe cherries may grow on the same coffee tree at the same time. Harvesting is therefore a quality decision: it determines which fruit enters processing. Four broad harvesting approaches can be distinguished by their selectivity, labour needs and implications for sorting.

1. Selective hand-picking — cherry by cherry

Ripe cherries are picked individually while unripe fruit remains for a later pass. This multi-pass method demands substantial time and labour, but gives close control over maturity and is common for smaller, high-quality lots. Even careful picking does not replace later checks.

2. Multi-pass stripping — selecting ripe branches

Branches carrying predominantly ripe cherries are stripped on more than one visit. Fruit is not inspected cherry by cherry; harvesting can be quicker than selective picking, but ripeness tends to be more variable and subsequent sorting matters more.

3. Single-pass stripping — one harvest

Cherries are removed from branches in a single pass whether perfectly ripe or not. The labour savings may be significant, but green, ripe and overripe fruit can be mixed. Prompt processing and careful sorting become particularly important.

4. Mechanical harvesting — efficiency on suitable terrain

Machines, often using vibration, detach cherries from the trees. They work best in plantations designed for access and machinery; steep or irregular agroforestry areas can be unsuitable. Labour requirements may fall, but machines can collect fruit of different maturities or cause damage, so sorting remains essential.

What determines quality?

Maturity, fruit health and the care and speed of subsequent processing are more important than the harvesting label alone. Unripe cherries can contribute green or astringent notes; damaged or very overripe fruit increases the risk of uncontrolled fermentation and microbial problems. Harvesting, preliminary sorting and processing must be considered together.

Sources: International Coffee Organization, Good Harvesting Practices (ED 1988/06), section 4.2 – https://ico.org/documents/ed1988e.pdf; Codex Alimentarius, CAC/RCP 69-2009, Code of Practice for the Prevention and Reduction of Ochratoxin A Contamination in Coffee, section 4.2 – https://dev.ico.org/documents/ed-2074e-ota.pdf

Washed processing

In washed processing, much of the skin and pulp is first removed mechanically. The remaining mucilage is broken down or removed through fermentation, mechanical treatment or a combination of both. Coffee then dries within its parchment. Time, temperature, hygiene and drying influence the result. Washed coffees are often described as clear and precise, but the method does not guarantee any particular flavour.

Sources: Várady et al. (2022), LWT, 172, 114245 – https://doi.org/10.1016/j.lwt.2022.114245

Natural processing (dry method)

In natural processing, the coffee cherry dries largely as a whole fruit. The dried outer layers are removed only afterwards. Even drying, frequent monitoring and protection from unwanted microbial growth are crucial. Natural coffees may show marked fruit-like or fermentative notes, depending on the original cherries and the way the process is managed.

Sources: Várady et al. (2022), LWT, 172, 114245 – https://doi.org/10.1016/j.lwt.2022.114245

Honey processing

In honey processing, the cherry skin is removed but part of the sugary mucilage remains on the parchment during drying. No honey is added: the name refers to the sticky texture. Terms such as yellow, red and black honey are used differently by different producers and are not universally standardised technical categories. Process management and careful drying are what matter.

Sources: Várady et al. (2022), LWT, 172, 114245 – https://doi.org/10.1016/j.lwt.2022.114245

Fermentation — microorganisms and coffee flavour

Fermentation is more than a way of removing sticky mucilage. Yeasts and bacteria transform sugars and other substances in coffee cherries, producing organic acids, alcohols and volatile compounds. They can also change precursors that later contribute to aromas formed during roasting.

Spontaneous fermentation involves the microorganisms naturally present in the fruit and its environment. Controlled approaches can adjust time, temperature, vessel material, oxygen exposure and sometimes starter cultures. The microbial population itself changes during the process; a duration alone cannot reliably predict the result.

In so-called anaerobic processes, oxygen contact is greatly reduced, for example in sealed vessels. This does not necessarily mean an entirely oxygen-free environment, nor does it prescribe a standard flavour. Carbonic maceration processes whole cherries in an atmosphere rich in carbon dioxide; the term comes from winemaking and is used for several technical variations in coffee.

These approaches may develop fruity, floral or wine-like impressions, but may also favour defects when hygiene or process control is inadequate. Neither “anaerobic” nor the shape of a tank determines a flavour by itself.

Sources: Elhalis, Cox & Zhao (2023), Coffee fermentation: Expedition from traditional to controlled process – https://doi.org/10.1016/j.afres.2022.100253; Coffee fermentation process: A review (2023) – https://doi.org/10.1016/j.foodres.2023.112793; controlled yeast experiment (2020), https://pubmed.ncbi.nlm.nih.gov/32771820/; Finca Mariposa: https://www.larbreacafe.com/pages/finca-mariposa-la-ferme-de-larbre-a-cafe

Drying, resting and hulling

After harvest and processing, coffee must be dried to a level suitable for reasonably stable storage and transport. Green coffee often targets a moisture content of about 10–12%, but even drying throughout the batch matters as much as the average number.

Cherries or parchment coffee may dry on raised beds, patios or in suitable mechanical dryers. Temperature, airflow, weather and regular turning affect the outcome. Prolonged moisture, rewetting or excessively aggressive drying can compromise quality.

After drying, coffee is often rested before sale or final preparation. At the dry mill, parchment or dried fruit residues are removed. The green coffee can then be sorted according to size, density and visually detectable defects.

Sources: ISO 9116:2025, specification, storage and shipment of green coffee: https://www.iso.org/standard/87698.html; Anokye-Bempah et al. (2023), moisture protection in storage and transport: https://doi.org/10.1016/j.jafr.2022.100478

Sorting, screen sizes and defects

After processing, green coffee is often sorted in several stages by size, density, colour and visible defects. Sieves separate bean sizes, gravity tables and optical sorters detect differences, and hand sorting may be used for some lots.

Traditional screen sizes are expressed in sixty-fourths of an inch. A “screen 18” opening measures 18/64 inch, a little over seven millimetres. A large bean is not necessarily a good bean: size is a trade and processing criterion, not a substitute for cupping.

Defect grading identifies black or damaged beans, foreign objects and signs of faulty processing. Allowed defects depend on the standard and contract. Sorting reduces avoidable problems, but the decisive sensory judgement is ultimately made in the cup.

Sources: Specialty Coffee Association, Coffee Standards and Protocols: https://sca.coffee/research/coffee-standards; International Coffee Organization: https://www.ico.org/

Specialty coffee and the 80-point threshold

For many years, specialty coffee was commonly identified in the trade through a 100-point cupping scale: under the traditional convention, coffees scoring at least 80 were considered specialty grade. Such scores are familiar to buyers and producers and offer a shared point of reference, but they cannot describe every sensory attribute or the full value of a coffee.

With its Coffee Value Assessment (CVA), the Specialty Coffee Association has introduced a broader framework. It distinguishes physical characteristics, descriptive sensory attributes, subjective or market-dependent quality assessments, and contextual information such as origin and processing. There is no simple one-to-one conversion from the old points into a single new universal score.

For espresso in particular, a number has limits. The same beans may taste very different according to roasting, extraction and the desired flavour profile. Standardised cupping is not identical to a particular espresso recipe. A score is useful but never tells the whole story.

Sources: Specialty Coffee Association, Coffee Value Assessment and its four assessment dimensions – https://sca.coffee/value-assessment/; SCA Standards 103–105 – https://sca.coffee/research/coffee-standards

Cupping — standardised coffee tasting

Cupping is a method of evaluating coffees under conditions designed to be as comparable as possible. Consistent sample preparation, dose, water, temperature and procedure make differences easier to recognise and discuss. The Specialty Coffee Association publishes current protocols within its Coffee Value Assessment framework, explicitly separating descriptive sensory observations from personal quality judgements.

Sources: Specialty Coffee Association – Standards SCA-102 to SCA-105 – https://sca.coffee/research/coffee-standards

From farmer to exporter — who moves green coffee?

A coffee harvest rarely travels directly from an individual smallholding to a European roastery. Before coffee is export-ready, cherries must be harvested, processed, dried, weighed and assessed. At a dry mill, parchment may be removed and beans sorted. Packaging, shipping documentation, transport arrangements and frequently financing of the harvest add further tasks.

Smallholders may organise themselves into cooperatives, which pool volumes, provide facilities, negotiate conditions or arrange training. Others sell to local collectors or processors; larger estates may operate their own processing equipment. Exporters assemble suitable lots and coordinate quality checks, documentation, customs, shipping and financial risks.

A cooperative does not necessarily eliminate all traders, nor is an exporter simply a dispensable markup. Without specialist skills, capital, warehouses or export authorisations, international sales would be difficult for many producers. Equally, an opaque chain can obscure how much of the final payment reaches the farm.

The most suitable arrangement depends on country, farm size, available services and the agreed terms. Responsible sourcing examines price, quality, traceability, contracts and the allocation of opportunities and risks.

Sources: International Trade Centre, The Coffee Guide (2021), chapters on participants, exporting, quality and contracts – https://digitallibrary.un.org/record/4090550; CBI, Buyer Requirements – https://www.cbi.eu/market-information/coffee/buyer-requirements.

World markets, pricing and direct trade

Coffee is one of the most important internationally traded agricultural products. Arabica is traded and hedged using New York futures markets, while London futures are important for Robusta. These quotations provide reference prices and tools for managing risk; they are not identical to what a farmer receives for cherries or processed coffee.

Actual contracts take account of origin, processing, defects, cup attributes, volume, currency, harvest date and agreed premiums or discounts. Between a farm and a retail pack lie financing, sorting, export, insurance, shipping, storage, quality control, roasting, packaging and distribution.

Exchange-linked contracts may refer to a futures price plus or minus a differential. For distinguished lots, buyers and sellers often negotiate price and quality specifications individually. Longer relationships may also specify recurring sensory profiles, quantities and delivery requirements.

Direct Trade is not a protected certification. It generally means a closer commercial relationship between a roaster and a grower, farm or cooperative. Importers or exporters may still perform important legal, financial and logistical work. The meaningful questions are who negotiates the price, how quality is assessed, what information is shared and how the partnership operates.

Sources: International Coffee Organization, price and market data – https://data.ico.org/overview; International Trade Centre, The Coffee Guide, 4th ed. (2021) – https://digitallibrary.un.org/record/4090550; Fairtrade International, pricing rules – https://www.fairtrade.net/ch-de/was-ist-fairtrade/fairtrade-ansatz/standards/mindestpreise-praemien.html.

From origin port to roastery — transport, storage and quality control

Following processing, drying and dry milling, green coffee is prepared for export. Depending on the lot, it may travel in sacks, bulk bags or approved bulk-container arrangements. Documentation and physical checks accompany the movement from agricultural harvest to international traded commodity.

Ocean transport requires care. Green beans absorb foreign odours and react to moisture. Condensation and water damage caused by changing temperatures are particularly problematic. Suitable packaging, clean dry containers and controlled warehousing all help protect quality.

At the destination port, coffee does not always go directly to the roastery. Specialist operators may arrange customs clearance, incoming inspections, weighing, sampling, storage and onward dispatch. Where necessary, they can clean, optically sort, grade by specific gravity or repack the beans. Romani, with facilities associated with Trieste and Genoa, and companies such as Pacorini illustrate this industry; naming them does not imply that they currently provide services to Amici.

These operations are often necessary even in direct trade. A direct commercial agreement between farm and roaster does not eliminate exporters, shipping companies, customs agents or port warehouses. What matters is each participant's function, how the quality is protected and whether the movement remains traceable.

Sources: International Trade Centre, The Coffee Guide (2021) – https://digitallibrary.un.org/record/4090550; ISO 8455:2011, Green coffee – Guidelines for storage and transport – https://www.iso.org/standard/44601.html; Romani S.p.A., Plant and coffee processing – https://www.romanige.it/en/plant-and-coffee-processing; Transport Information Service, Coffee – https://www.tis-gdv.de/tis_e/ware/genuss/kaffee/kaffee-htm/.

Drum or hot air — two approaches to roasting

Roasting equipment differs in the way heat is transferred to beans. In a drum roaster, the moving beans are heated by a combination of hot air, contact with surfaces and radiant heat. In a hot-air or fluid-bed roaster, airflow contributes a particularly large share of heat transfer and can also keep the beans moving.

Both designs allow different roasting profiles. Temperature management, airflow, batch size and roasting time determine how heat penetrates the coffee and which flavour compounds form. A fruity, balanced or intense roast cannot be inferred from the machine type alone. Successful roasting depends on green coffee, technology and experience, and on repeating the intended result reliably.

Sources: International Coffee Organization, Coffee Guide: https://www.ico.org/; Specialty Coffee Association, Coffee Research: https://sca.coffee/research

What happens during roasting

Green coffee is relatively dense, still contains water and smells entirely different from roasted coffee. Much of the aroma we associate with the cup develops only when the beans are heated. In the early stages moisture evaporates; later, thermal and chemical transformations become increasingly important.

The physical transformation is striking. Beans become lighter and larger: depending on the profile, they commonly lose about 15–20% of their initial mass, while their volume may increase by roughly 50–100%. Pores and gas cavities form inside, and the roasted beans become more brittle and easier to grind.

Several chemical processes occur together. Maillard reactions involving sugars and amino compounds, along with other thermal degradation and transformation pathways, create a complicated mixture of volatile substances. Researchers have identified hundreds, in some analyses approximately 800 or more, distinct volatile molecules in roasted coffee. These are not the same as 800 separately perceptible aromas: a much smaller group is particularly influential.

First Crack is the audible cracking associated with pressure and structural changes inside the bean. It is an important roaster's landmark but not a universal temperature or a precise line between good and bad roasting. A possible Second Crack indicates further structural change at more advanced roast levels. Two batches can finish at similar colours yet taste different because their time and temperature histories differ. Coffee must cool rapidly after roasting to prevent unwanted continued development.

The roast curve — temperature and heat input over time

The roasting machine is preheated before green beans are loaded. Charging it with relatively cool beans lowers the displayed bean-probe temperature. This initial dip does not mean that the beans themselves are cooling; they are already absorbing heat. The lowest reading is called the Turning Point. Afterwards the measured bean temperature rises, usually faster at first and more slowly later in a typical profile. The curve is not an exponential rise and there is no single correct shape for every machine or coffee.

Real roasters often record several temperatures rather than just one: a bean-probe reading, environmental or exhaust-air measurements and the changes in these readings over time. Because probe placement and batch size affect measurement, the Turning Point is a feature of the recorded trace and should not be interpreted as the green beans physically becoming colder after loading. Heat input, airflow and Rate of Rise have to be read together. Stepping down burner power can precede a visible change in the temperature curve; this delay illustrates the thermal inertia of the equipment and coffee mass.

The bean-temperature curve is only part of the picture. Rate of Rise (RoR) describes how many degrees per minute the measured bean temperature increases. Temperature may continue upwards even as RoR declines. Adjustments to burner or heating power and airflow change the supply and transfer of energy, but the heated metal and the bean mass have thermal inertia: their response is delayed. A change in gas setting will not instantly produce an equal change in bean temperature. Profile control therefore requires planning ahead rather than reacting to each reading in isolation.

Drying, browning and Maillard reactions, First Crack and the subsequent development period provide useful landmarks. Their duration, temperature and relationship to heat input influence the final flavours. A roasting profile records the journey rather than merely an end temperature, making repeatable results possible.

Endothermic and exothermic — where heat comes from

An endothermic process consumes heat; an exothermic one releases it. Early roasting is dominated by heat absorption, not least because evaporating water requires energy. Later chemical transformations include exothermic reactions, although many simultaneous reactions make it misleading to treat roasting as a simple switch from one state to the other. First Crack is a useful practical marker, not a precise thermodynamic boundary.

The roaster must therefore control both the heat entering the beans and the heat already stored in the equipment and bean mass. High retained temperatures can continue to drive changes even after burner power is reduced.

Why beans must be cooled immediately

Once the intended roast is reached, coffee is discharged into a cooling tray, usually with vigorous airflow and stirring. The goal is to stop further thermal transformation rapidly. Hot beans retain considerable energy and would otherwise continue roasting even outside the heated drum. The principle resembles plunging cooked food into an ice bath to stop further cooking, although commercial coffee is generally air-cooled. Precisely controlled cooling is part of successful roasting, not an afterthought.

Sources: Wei & Tanokura (2025), Changes in coffee beans during roasting, https://doi.org/10.1016/B978-0-443-13868-3.00072-7; experiment on roast mass loss, International Journal of Food Science and Technology (2025), https://academic.oup.com/ijfst/article/60/2/vvaf189/8262800; Physical properties of coffee beans during roasting, Biosystems Engineering (2018), https://www.sciencedirect.com/science/article/abs/pii/S0926669017308300; Münchow et al. (2020), Roasting Conditions and Coffee Flavor: A Multi-Study Empirical Investigation, Beverages 6(2), 29 – https://doi.org/10.3390/beverages6020029; Fabbri et al. (2011), Numerical modeling of heat and mass transfer during coffee roasting process, Journal of Food Engineering – https://doi.org/10.1016/j.jfoodeng.2011.02.030; Development of coffee bean porosity and thermophysical properties during roasting (2024), Journal of Food Engineering – https://doi.org/10.1016/j.jfoodeng.2024.112096; Roast curves, turning point and probe measurement: Mill City Roasters (2026), How to Read a Roast Curve – https://millcityroasters.com/blogs/blog/how-to-read-a-roast-curve; Cropster (2026), About Rate of Rise (RoR) – https://help.cropster.com/en_US/using-roasting-intelligence/about-rate-of-rise-ror; Anokye-Bempah et al. (2025), A universal color curve for roasted arabica coffee, Scientific Reports – https://doi.org/10.1038/s41598-025-06601-w

Roast levels — from light to dark

Roast level indicates how far coffee beans have been transformed by heat, influencing colour, structure and flavour. Yet final colour is not the whole roasting profile: time and heating rate influence the compounds produced or lost.

Light roasts often make floral, fruit-like and more vivid acidic characteristics easier to perceive. Medium roasts may combine elements of origin with nutty, caramel and chocolate impressions. Carefully produced dark roasts deserve more nuanced treatment than the idea that dark always means burnt: they may offer cocoa, dark chocolate, roasted nuts and rich, rounded body, particularly in certain Italian espresso styles. Pushing the roast too far may, however, emphasise bitterness, smoke or ash and obscure fine origin traits.

The terms light, medium and dark have no universal commercial definition. Darker roasted coffee is neither necessarily inferior nor automatically higher in caffeine. The goal, green-coffee quality and mastery of the roasting process remain decisive.

Sources: Chemical Changes in the Components of Coffee Beans during Roasting (2015), https://doi.org/10.1016/B978-0-12-409517-5.00010-3; study of roast degree, chemistry and sensory properties (2020) – https://pubmed.ncbi.nlm.nih.gov/32559595/

The blend — the art of combining coffees

An espresso blend can be a deliberate composition rather than a compromise. Single-origin coffee resembles a solo instrument, foregrounding one origin's character; a blend is more like an orchestra. Individual coffees may contribute sweetness, acidity, body, floral tones or chocolate depth. What matters is the harmony of the whole, not how loudly each component performs alone.

In pre-blending, green-coffee components are combined before roasting and follow the same roasting profile. That can be efficient but requires components suited to roasting together. In post-blending, coffees are roasted individually before being mixed, allowing different profiles at the cost of added planning and production effort. Neither approach is universally superior.

A successful blend is not a fixed recipe. Harvests, availability, moisture and sensory properties change from season to season. Identical percentages of the component coffees do not guarantee an identical flavour. New purchases must be assessed and the formula adjusted when needed so the intended cup stays recognisable over time. More components create more interactions but can also help buffer variation in individual lots.

Sources: Specialty Coffee Association, Coffee Value Assessment – https://sca.coffee/value-assessment/; World Coffee Research, Sensory Lexicon – https://worldcoffeeresearch.org/; editorial description of the Amici blend based on company information

Degassing and freshness

Roasted coffee is not chemically static. Roasting creates numerous volatile compounds responsible for much of its aroma. Carbon dioxide is also trapped in the porous bean structure. After roasting, several processes proceed simultaneously: CO₂ escapes, volatile aromas evaporate or react, and atmospheric oxygen can oxidise susceptible compounds.

Why oxygen changes coffee's aroma

Oxygen can react with unsaturated constituents of coffee oils and several odour-active molecules. Desired compounds may diminish or change while new oxidation products develop, including aldehydes that may contribute stale, cardboard-like or eventually rancid notes. Hexanal is one analytical marker, but no single molecule captures all sensory ageing.

Cardelli and Labuza (2001) found that, for their tested ground coffee and storage conditions, raising the partial pressure of oxygen from 0.5 to 21.3 kPa was associated with an approximately twentyfold acceleration of the studied staling process. This is not a prediction of how long an opened paper portion will remain sensorially unchanged; it does show why a substantial oxygen barrier is important in protective packaging.

The sulfur-containing key aroma compound 2-furfurylthiol is a useful example: present in small amounts, it contributes strongly to the impression of freshly roasted coffee, and it is chemically vulnerable. Different aromatic substances have different stabilities and perceptual thresholds.

Loss of aroma is not the same as oxidation

When coffee is exposed to air, volatile molecules escape into the surroundings even without chemically reacting with oxygen. Oxidation and other chemical reactions occur alongside this physical loss. Delicate fresh notes can therefore weaken before explicitly rancid or stale tastes develop. Coffee can lose much of its characteristic expression without becoming unsafe to drink.

What happens in the first hours and following days?

Once protective packaging is opened, accessible surfaces come into contact with air. The speed of change depends on grind size, quantity, temperature, humidity, air circulation, roast, packaging and the specific molecules present. Some aroma loss begins at once, while oxidation products may become more significant with continued exposure. There is no defensible universal hour at which all coffees suddenly become stale.

Chemical measurements and human acceptance do not reach the same threshold at the same time. Under Anese, Manzocco and Nicoli's specific conditions (ground coffee at 30°C with repeated opening), the estimated time to olfactory rejection by half of the panel ranged from 13 to 23 days according to water activity. This was a judgement of the smell of coffee grounds, not of prepared espresso, and cannot be used as a universal consumption deadline.

Why an unpacked paper portion is sensitive

A paper filter portion contains already ground coffee with a large exposed surface. The filter paper allows brewing water through and is not an airtight oxygen barrier. Once its protective outer wrapper is removed, volatile compounds may escape and oxygen and humidity can reach the grounds. Changes may be perceptible within hours to a very sensitive observer, but this does not establish a general twelve-hour shelf-life limit.

An outer pack with an effective oxygen and moisture barrier serves a different purpose from the porous paper surrounding the coffee. The paper portion is designed to allow brewing water to reach the grounds; it is not designed to maintain the original aroma indefinitely after unwrapping. Any time-based sensory estimate must refer to the particular coffee, packaging, temperature and test design.

Do high-quality coffees age differently?

Coffees differ in origin, chemistry, processing, roasting and which aroma compounds make them distinctive. Higher initial quality does not automatically mean faster oxidation; chemical ageing rates and the moment changes become noticeable are separate matters. A highly nuanced floral coffee may lose recognisable notes early, whereas a fuller, darker flavour profile may change in a different way. There is no general rule linking cupping score to hours of freshness.

How differently do people notice ageing?

Individuals vary in smell sensitivity, training, familiarity with a coffee and the circumstances of tasting. Someone who knows a particular profile intimately may detect small departures, especially in side-by-side comparisons. A gradual change during daily consumption may be much less obvious. Analytical evidence of ageing does not mean everyone experiences the same decline at the same moment.

Temperature — why cooler coffee generally ages more slowly

Many chemical reactions proceed more slowly at lower temperatures, while the mobility and evaporation of volatile compounds are also temperature-dependent. Comparisons of roasted coffee stored at 5°C and 20°C have found smaller changes in certain aroma compounds under cooler conditions. Freezing can substantially slow processes during long-term storage; there is no universal equation to convert a temperature difference into a precise additional shelf life.

The temperature dependence of many chemical reactions is often described using the Arrhenius relationship, but coffee ageing is not governed by a single reaction or a universal shelf-life multiplier. Different aromas, oxidation pathways and physical losses respond differently to storage conditions. In an experimental comparison of coffee stored at 5°C and 20°C, lower-temperature samples showed smaller changes in selected volatile compounds over the study period. Cool storage therefore slows some mechanisms but cannot replace protection from oxygen and humidity.

Freezing, thawing and temperature changes

For storing coffee, the chief practical risk is exposing still-cold beans or grounds to warm, humid air. Moisture may condense on them and affect their stability and, for grounds, flow and brewing behaviour. Coffee can be frozen in small, sealed, moisture-resistant portions and allowed to reach room temperature before the pack is opened. Repeated thawing, opening and refreezing should generally be avoided.

If a frozen package is opened directly in warmer, humid air, condensation can form on still-cold beans or grounds. For longer storage, one practical approach is to keep the package closed while it warms to room temperature. Brewing directly from frozen coffee is a different question: the initial temperature may affect extraction, without establishing any universal damage from a so-called temperature shock.

This is different from brewing an individually removed frozen dose directly. Contact with hot brewing water is not intrinsically harmful merely because the coffee was previously frozen. A cooler starting temperature can, however, change heat transfer during brewing and potentially extraction. This does not support any universal claim of improvement or damage due to “thermal shock”. Grinding frozen whole beans may also affect particle size distribution.

Protected resting rather than uncontrolled air exposure

Freshly roasted coffee continues to release CO₂ even when shielded from the environment. A controlled resting stage can be beneficial. In inert-gas storage, nitrogen replaces much of the oxygen-containing air. Degassing may produce a small positive pressure inside a suitable closed vessel, controlled by a safety valve. Oxygen reduction protects aroma while CO₂ release and retention are managed. This is very different from leaving an unwrapped coffee portion exposed to room air.

Sources: Cardelli & Labuza (2001), effect of oxygen and water activity on coffee storage – https://doi.org/10.1006/fstl.2000.0732; Anese, Manzocco & Nicoli (2006), secondary shelf life of ground coffee at 30°C – https://doi.org/10.1021/jf060204k; Smrke et al. (2022), storage after opening – https://doi.org/10.1016/j.fpsl.2022.100893; Effect of Temperature and Storage on Coffee’s Volatile Compound Profile and Sensory Characteristics (2024), Foods – https://doi.org/10.3390/foods13243995; The Effects of Storage Temperature on the Aroma of Whole Bean Arabica Coffee Evaluated by Coffee Consumers (2018), Beverages – https://doi.org/10.3390/beverages4030068; Uman et al. (2016), grinding chilled beans – https://doi.org/10.1038/srep24483; Specialty Coffee Association, Samo Smrke, The Science of Coffee Freshness (2019), on condensation risk – https://sca.coffee/sca-news/podcast/81/the-science-of-coffee-freshness-samo-smrke-expo-lectures-2019-6lrbe; Information on Amici's production process: company information. The studies cited do not establish a universal freshness limit for all pack formats. The separately marked Amici recommendation is based on our own sensory panel assessments.

Why coffee needs packaging — freshness and environmental impact

Coffee is at its best when roasting aromas are protected. Packaging is designed first to limit exposure to oxygen, and also to reduce contact with humidity, foreign odours, light and heat. Ground coffee is especially demanding because its enlarged surface facilitates the loss of volatile compounds and oxidative changes.

Primary shelf life concerns the period during which coffee retains its intended qualities in an unopened package. Technical options include oxygen-barrier bags, inert-gas flushing, barrier films, one-way valves for whole beans and individually protected portions. A one-way valve chiefly permits the CO₂ released by coffee to escape without admitting similar volumes of surrounding air.

Secondary shelf life begins with opening. Each time a pack is opened, fresh air reaches the coffee and some remains after closure. Especially with ground coffee, aroma intensity and freshness may decline over days. When this becomes noticeable differs from person to person. A clear difference in a direct comparison does not mean that the coffee is unacceptable to every ordinary consumer, and there is no universal number of days after which coffee becomes unusable.

Anese, Manzocco and Nicoli (2006) investigated secondary shelf life using dark-roasted ground Arabica at 30°C. Containers were opened for one minute each day. Participants smelled the powder and decided whether they would still use it. Water activity (a_w) describes water available to physical and chemical processes; it is not simply moisture content. Higher water activity led to earlier rejection.

The estimated point at which half of panellists rejected the smell was approximately 20 days at a_w 0.09, 23 days at 0.17, 22 days at 0.23, 17 days at 0.36 and 13 days at 0.44. These are laboratory results under specific conditions, not guaranteed use-by dates for domestic coffee. At the sensory rejection point, the measured headspace signal of volatile compounds averaged around 60% of its initial level. That neither means 60% of all aroma molecules had been lost nor measures the taste of a brewed espresso.

Water activity (a_w)	Estimated days	95% confidence interval (days)
0.09	20	17–23
0.17	23	19–26
0.23	22	16–28
0.36	17	11–23
0.44	13	10–16

For practical storage, whole beans should be kept tightly closed, cool and dry, and ground just before brewing. Ground coffee should be used relatively promptly after opening. A large pack makes sense if it will be consumed quickly; separately protected portions avoid repeatedly exposing unused grounds to the atmosphere but require additional packaging.

This creates an environmental trade-off. A light flexible film can reduce materials and transport burden but may be difficult to recycle; glass is recyclable and sometimes reusable yet heavier. More recyclable materials do not always offer equivalent oxygen and moisture barriers. A proper environmental assessment must consider material, logistics, lifespan, possible coffee waste and actual end-of-life treatment together.

Source of the figures: Anese, Manzocco & Nicoli (2006), Table 2. The stated water activity and experimental conditions do not establish a universal storage recommendation.

Sources: Anese, Manzocco & Nicoli (2006), Modeling the Secondary Shelf Life of Ground Roasted Coffee, J. Agric. Food Chem. 54, 5571–5576 – https://doi.org/10.1021/jf060204k; Cardelli & Labuza (2001), oxygen and shelf life – https://doi.org/10.1006/fstl.2000.0732; Smrke et al. (2022), storage after opening – https://doi.org/10.1016/j.fpsl.2022.100893; temperature comparison 5 °C/20 °C (2024) – https://doi.org/10.3390/foods13243995; The environmental impact of a specific package requires a product-specific life cycle assessment.

Grind sizes — the right particle size for each method

Grinding increases the coffee surface exposed to water. Under otherwise comparable conditions, finer particles offer more surface and may release compounds faster. In a flowing coffee bed, grind size also changes resistance to the movement of water.

Espresso usually calls for a fine grind; many hand-filter methods use medium-fine to medium, while French press generally favours coarser particles. Turkish coffee traditionally uses an exceptionally fine powder. These are starting points rather than fixed rules: the right grind depends on the grinder, roast, recipe and desired cup.

Every grind setting is part of a complete brewing recipe. For espresso, dose, distribution, pressure and beverage yield all matter; for hand filtering, the coffee-to-water ratio, filter, pouring pattern and contact time are especially important. The articles on espresso, pour-over, brew ratios and extraction discuss these factors in detail. When adjusting a recipe, change one variable at a time wherever possible.

Sources: Specialty Coffee Association, Brewing Resources: https://sca.coffee/research; UC Davis Coffee Center: https://coffeecenter.ucdavis.edu/

The coffee grinder — why grinding matters

Grinding breaks a bean into many particles, greatly increasing the area available for water to dissolve soluble substances. Grind size and the distribution of particle sizes influence both the flow of water through the bed and the substances reaching the cup.

Blade grinders break beans relatively irregularly; burr grinders using flat or conical burrs offer more reproducible settings. The average particle size is only one consideration. The mixture of larger particles and extremely small “fines” affects both exposed surface and resistance to water flow. No burr shape can universally guarantee the best cup: geometry, condition, calibration and the coffee itself interact.

Small changes in grind are particularly evident in espresso. If a shot runs too quickly under otherwise stable conditions, grinding finer may help; if it runs too slowly, a coarser grind may be appropriate. The correct setting is not a permanent number on the dial. In a busy café it may need adjusting several times during the day.

Temperature — why a grinder's behaviour changes during the day

Cold beans do not necessarily fracture in the same way as warm ones. Research has shown that bean temperature can change the particle size distribution: under the investigated conditions, colder beans produced a finer and narrower distribution on average. Burrs also warm during intensive operation, so the same mechanical position can yield different grounds at different times.

Humidity, static electricity and coffee freshness

Grinding creates electrostatic charges. The extent to which particles cling to one another or to the grinder depends partly on moisture in the coffee and its surroundings. Roasted beans also change as they age. Temperature, relative humidity and freshness can jointly affect dosing, distribution and extraction time. A weather change does not automatically require adjustment: the actual brew must be observed.

Baristas therefore dial in against a repeatable recipe: similar dose, target yield and time, followed by tasting. If the result drifts, they can change the grind without altering several other parameters at once.

Sources: Uman et al. (2016), The effect of bean origin and temperature on grinding roasted coffee, Scientific Reports – https://doi.org/10.1038/srep24483; Mohr et al. (2024), Moisture-controlled triboelectrification during coffee grinding, Matter – https://doi.org/10.1016/j.matt.2023.11.005; study of fines and repeated grinder adjustment, Scientific Reports (2024) – https://doi.org/10.1038/s41598-024-55831-x; Cameron et al. (2020), Systematically Improving Espresso – https://doi.org/10.1016/j.matt.2019.12.019

Water — the underestimated ingredient

Most of a cup of coffee is water. Its minerals and chemistry influence flavour and extraction. Calcium, magnesium and bicarbonate ions are particularly relevant.

Calcium and magnesium can interact with coffee compounds. Bicarbonate helps buffer acidity and influences how clearly it is perceived. Very hard water also increases the risk of scale in equipment.

There is no single ideal composition for every coffee and machine. Anyone noticing dull flavour or excessive scaling should examine local water hardness and consider appropriate treatment compatible with the machine manufacturer's guidance.

Sources: Hendon et al. (2014), The Role of Dissolved Cations in Coffee Extraction: https://doi.org/10.1021/jf501687c

Brewing temperature

Water temperature influences the speed and composition of extraction. Many hot-coffee recipes use approximately 90–96°C, but this is a common point of reference rather than a rule for every bean and method.

Higher temperatures generally accelerate many extraction processes. Their sensory effect depends, however, on grind, contact time, beverage yield, roast and water chemistry. One specific temperature does not invariably create more sweetness or bitterness.

Repeatability is crucial. To compare cups meaningfully, keep brewing temperature as stable as possible and deliberately change it only after other variables are under control.

Sources: Specialty Coffee Association, Coffee Brewing Standards and Research: https://sca.coffee/research; UC Davis Coffee Center: https://coffeecenter.ucdavis.edu/

Crema — the foam on espresso

Crema is the fine foam that appears on the surface of many espressos. Carbon dioxide released from coffee under pressure forms small bubbles, while components of the liquid help stabilise them for a time.

Crema volume and persistence depend on the beans, roast level, freshness, grind and brewing conditions. Blends containing Robusta often develop pronounced crema. Very recently roasted coffee may also release substantial amounts of gas.

Crema is characteristic of many espressos, but not a reliable quality seal: a thick layer proves neither balanced extraction nor pleasant flavour. It is one part of a complex beverage containing dissolved compounds, tiny oil droplets and suspended fine particles. The article on espresso physics explains how these phases interact. Ultimately the whole cup matters more than its surface.

Sources: Neglected Food Bubbles: The Espresso Coffee Foam (2011) – https://pmc.ncbi.nlm.nih.gov/articles/PMC3140933/; Investigation of the factors that affect the volume and stability of espresso crema (2019) – https://www.sciencedirect.com/science/article/pii/S0963996918307105

Filter coffee — pour-over

In pour-over brewing, hot water is poured by hand over coffee held in a filter. It passes through the coffee bed while paper or another filter material retains particles, and the beverage collects in a cup or server. The method looks simple yet offers considerable control.

Important variables are coffee and water quantities, grind, water temperature, filter material, contact time and the speed and distribution of pouring. They interact: a finer grind may slow flow and alter extraction; a different pouring pattern changes wetting and water movement. There is no single magic number for an excellent cup.

A framework for filter brewing — brew ratio and the Brewing Control Chart

There is no universally recognised equivalent of the Italian espresso “five Ms” for pour-over. One established reference is the Brewing Control Chart, which relates beverage strength (total dissolved solids, TDS) to extraction yield. Historical reference ranges often cite approximately 18–22% extraction and 1.15–1.35% TDS for filter coffee. These are comparison tools rather than precise boundaries between good and bad taste.

For many filter recipes, the brew ratio is expressed as the weight of dry coffee to the amount of brewing water poured in, unlike espresso recipes that often compare dose with the weight of the beverage collected. Water quality, technique and personal preference determine where the most satisfying result lies.

Sources: Specialty Coffee Association, Brewing Best Practices (SCA, 2019) – https://www.scith.coffee/wp-content/uploads/2021/03/SCA-Protocols-_-Best-Practices.pdf; SCA Home Coffee Brewers Standard 310-2021 – https://coffeegeek.com/wp-content/uploads/2023/10/SCAGoldCupStandard.pdf; UC Davis Coffee Center – https://coffeecenter.ucdavis.edu/

The Chemex

The Chemex is a glass coffee brewer conceived by Peter Schlumbohm and introduced in 1941. Its sculptural hourglass form became an emblem of functional industrial design. The coffee is prepared as a manual pour-over, usually with the manufacturer's relatively thick paper filters.

The filter retains many fine particles and some coffee oils, often giving a clear-bodied, clean-tasting beverage. As with other filter methods, results depend on the dose, grind, filter, water temperature and pouring technique. The Chemex is both a distinctive design object and a brewing system whose operation remains straightforward.

Sources: Museum of Modern Art, Peter Schlumbohm, Chemex Coffee Maker (1941): https://www.moma.org/collection/works/1847; Chemex, company history: https://chemexcoffeemaker.com/pages/85-years

French press

In a French press, relatively coarse coffee grounds are immersed in hot water for several minutes. A mesh plunger is then lowered to separate much of the coffee from the liquid. Unlike paper filters, the metal mesh lets more oils and fine particles through, often creating a fuller body and more sediment in the cup.

The result depends on dose, grind, water temperature, steeping time and how gently the grounds are disturbed or the plunger is pressed. A French press does not require an extremely coarse grind in every recipe, nor does the plunger stop extraction completely: leaving the drink on the sediment may continue to change it. Decanting after brewing improves consistency.

Sources: Specialty Coffee Association, Brewing Fundamentals: https://sca.coffee/research; UC Davis Coffee Center: https://coffeecenter.ucdavis.edu/

Cold brew — extraction with cold water

Cold brew means extracting coffee with cold or room-temperature water rather than brewing hot coffee and chilling it afterwards. Both techniques can be served cold, but their extraction processes are different. With low-temperature extraction, dissolving and diffusion are generally slower, so time becomes especially important.

How does cold extraction work?

Ground coffee remains in contact with water for an extended period, often around 8–24 hours depending on grind, water temperature, concentration and method. Many recipes rely on immersion and later filtration; others allow cold water to drip gradually through the grounds. Grind and time must be balanced to avoid unwanted sediment and uneven extraction.

Flavour, acidity and caffeine

Cold brew is often perceived as smooth and less sharply acidic, although this is not a guarantee of a higher pH or lower total acid content. The composition and perceived balance differ from hot coffee. Cold brew is not automatically lower in caffeine: dose, concentration, extraction time and serving dilution can make the final drink more or less caffeinated than hot-brewed coffee.

From concentrate to nitro cold brew

Concentrated cold brew is made using relatively little water and is diluted for serving. Cold drip is a related method where water moves slowly through the grounds. Nitro cold brew is infused with nitrogen to create a characteristic cascading, creamy foam; it should not be confused with an inherently higher-quality extraction.

Hygiene and storage

Cold extraction does not sterilise a drink. Clean equipment, suitable water, hygienic handling and prompt refrigerated storage are important, especially because prolonged steeping occurs at temperatures that may allow microbes to persist or grow. Without validated processing, no blanket shelf-life claim should be made for homemade cold brew.

Sources: Fuller & Rao (2017), The Effect of Time, Roasting Temperature, and Grind Size on Caffeine and Chlorogenic Acid Concentrations in Cold Brew Coffee – https://pmc.ncbi.nlm.nih.gov/articles/PMC5740146/; Cordoba et al. (2019), Effect of grinding, extraction time and type of coffee on the physicochemical and flavour characteristics of cold brew coffee – https://doi.org/10.1038/s41598-019-44886-w; Lachenmeier et al. (2021), Cold Brew Coffee—Pilot Studies on Definition, Extraction, Consumer Preference, Chemical Characterization and Microbiological Hazards – https://pmc.ncbi.nlm.nih.gov/articles/PMC8071471/; Rao et al. (2020), Physiochemical Characteristics of Hot and Cold Brew Coffee Chemistry – https://pmc.ncbi.nlm.nih.gov/articles/PMC7404565/

Milk — cappuccino, latte and flat white

Milk changes coffee's flavour, texture and temperature. Its proteins can stabilise fine air bubbles during steaming, while fat and dissolved sugars contribute body and mouthfeel. Skilled steaming produces microfoam with a fine, integrated texture instead of a separate cap of large bubbles.

A cappuccino traditionally balances espresso, warm milk and foam in a relatively small cup, often around 150–180 ml in total. A flat white commonly uses a more coffee-forward balance and fine-textured milk, often around 150–200 ml, while a caffè latte is generally served larger, approximately 200–300 ml. These are useful ranges, not globally fixed definitions; local coffee cultures and cafés use different recipes.

Why warm milk can taste sweeter

Heating milk to the temperatures normally used for steaming, commonly around 55–65°C, does not caramelise lactose. True caramelisation requires much higher temperatures. Warmth, milk's naturally present lactose, foam texture and the interaction with coffee bitterness can nevertheless increase the perception of sweetness. Excessively hot milk may lose freshness, impair texture or develop cooked notes.

When steaming begins, air is incorporated into the milk; controlled circulation then breaks larger bubbles into a finer, more uniform texture. Milk proteins help stabilise these gas–liquid interfaces. Fat content and temperature affect the resulting mouthfeel, while excessive heat can make the foam less stable and introduce cooked-milk flavours.

Sources: Specialty Coffee Association, Barista Skills – https://sca.coffee/education; International Dairy Foods Association, Milk Science – https://www.idfa.org/; Science & Food, The Science of Steamed Milk (2015) – https://www.scienceandfood.org/the-science-of-steamed-milk-understanding-your-latte-art/; Deeper Roots Coffee, Milk Science (2026) – https://www.deeperrootscoffee.com/continued-education/milk-science-rl9g8; example beverage volumes: https://www.bean.ch/wp-content/uploads/200430_DH_Zubereitungsarten.pdf

Brew ratio — the relationship between coffee and water

A brew ratio compares the quantity of ground coffee with another relevant quantity in the brewing process. The convention depends on the method. For filter coffee it normally expresses dry coffee relative to the brewing water added: for instance, 20 g coffee to 320 g water corresponds to 1:16.

For espresso, recipes more commonly compare the dry dose with the beverage collected. A 18 g dose yielding 36 g espresso is described as a 1:2 beverage ratio. These two ratios are not interchangeable, because a filter bed retains some brewing water while espresso recipes measure the outflow.

A ratio helps achieve repeatability but is not a guarantee of ideal extraction. Grind size, contact time, pressure, temperature, water chemistry and the coffee itself determine how the same ratio tastes.

Sources: Specialty Coffee Association, principles of brew ratio – https://sca.coffee/research; Smrke, Water and Coffee Acidity: How to Adapt Your Water for Different Extraction Methods, SCA – https://sca.coffee/sca-news/25/issue-9/english/water-and-coffee-acidity-how-to-adapt-your-water-for-different-extraction-methods-25-magazine-issue-9-pxjby; Cameron et al. (2020), Matter – https://doi.org/10.1016/j.matt.2019.12.019

Extraction — what coffee really is

Coffee brewing is the controlled transfer of soluble and dispersible substances from ground coffee into water. The final beverage contains a complex mixture of acids, caffeine, aromatic compounds and other dissolved substances. Depending on the method, it may also hold fine particles and oils. Dose, grind, water, temperature, time and flow all influence which compounds reach the cup.

Under-extraction — when too little is dissolved

If the intended flavour compounds are insufficiently extracted, a coffee may taste unusually sharp, thin, hollow, green or lacking in sweetness. A coarse grind, short contact time, low temperature or uneven wetting may contribute. Acidity alone, however, does not prove under-extraction: some well-extracted coffees are naturally lively and acidic.

Balanced extraction — the intended cup

A balanced extraction occurs when sweetness, acidity, bitterness, aroma and body come together in the way the coffee and chosen recipe are meant to express. This is not a fixed numerical point; a light filter coffee and a dark espresso may have very different balances yet both be well made.

Over-extraction — when unwanted impressions dominate

Extracting too extensively may bring harsh bitterness, drying sensations or a rough, astringent finish. It can be encouraged by an unsuitable grind, very long contact or excessive yield. But bitterness is also a natural constituent of coffee, especially in darker roasts, and does not by itself diagnose over-extraction.

Extraction yield and strength are different

Extraction yield indicates the share of the dry coffee mass dissolved into the drink. Beverage strength describes the concentration of dissolved substances, commonly reported as total dissolved solids (TDS). A strong cup can be poorly extracted, and a weaker one may be extracted extensively. Traditional Brewing Control Charts used roughly 18–22% extraction for filter coffee; these figures are reference ranges, not universal espresso targets.

Why one cup may contain both under- and over-extracted areas

In a coffee bed with uneven flow or channeling, some regions receive disproportionately much water while others are barely reached. A single average extraction yield can conceal these differences. Brew time and total dissolved mass alone cannot explain every sensory defect.

What can be changed for the next brew?

When a coffee tastes notably thin and sharply sour, a slightly finer grind or more even wetting may help. Unpleasant drying bitterness can prompt examination of grind, water quantity and contact time. Espresso also requires attention to distribution, tamping and the pressure profile. Change one parameter at a time and taste again. The following articles explore the mechanisms further.

Sources: Specialty Coffee Association, Brewing Control Chart (2019) – https://static1.squarespace.com/static/587af1d4db29d69a1a226b95/t/60aece65e4f2134d99f6e646/1622068839009/SCA%2BBrewing%2BChart%2B-%2BRevised%2BMarch%2B2019-US-Letter.pdf; SCAE, European Extraction Preferences in Brewed Coffee – https://static1.squarespace.com/static/584f6bbef5e23149e5522201/t/59a5e977c534a545652c48f8/1504045435759/SCAE_Gold_Cup_European_Extraction_Preferences.pdf; Cameron et al. (2020), Systematically Improving Espresso, Matter, 2, 631–648 – https://doi.org/10.1016/j.matt.2019.12.019

Channeling, distribution and tamping

In espresso, hot water under pressure passes through a compact bed of finely ground coffee. It follows paths of lower resistance. Voids, cracks or regions of uneven density may create channeling: some areas are rinsed disproportionately while others are underexposed, leading to uneven extraction. Channeling cannot be diagnosed with certainty from shot time or a single pressure reading.

Distribution — preparing an even coffee bed

Freshly ground coffee may clump or pile unevenly in the basket. Careful levelling and, if needed, breaking up larger clumps aim to create a fairly uniform packing density across the whole basket. Gaps at the edge can have a disproportionate influence on subsequent flow.

Tamping — the last step before extraction

Tamping is the controlled compression of evenly distributed grounds using a fitting tool called a tamper. It creates a cohesive, level coffee puck. Compression changes porosity and permeability, providing resistance to brewing water rather than leaving loose grounds to be pushed around freely.

Good practice emphasises even distribution before tamping, a well-fitting tamper and straight, repeatable pressure. A tilted puck may create differences in depth and density. Greater force is not an end in itself: once the puck is adequately compressed, pressing harder does not necessarily improve extraction. In one series of 150 espressos comparing forces of 10, 15 and 20 kg, shot time and dissolved-solids concentration showed no statistically significant difference.

Why tamping alone cannot prevent channeling

A visually flat puck may still flow unevenly. Grind and particle-size distribution, dose, basket geometry, wetting and brewing pressure matter too. The aim is repeatable, even preparation, not maximum puck hardness. With manufactured paper coffee portions, compression is normally part of portion production, so the user does not tamp manually.

Sources: study of espresso extraction and coffee-bed compression, Journal of Food Engineering (2022) – https://www.sciencedirect.com/science/article/pii/S0260877422003557; Kaffeemacher, 150-espresso investigation of tamping force (2025) – https://kaffeemacher.de/en/blogs/kaffeewissen/press-pressure-tamper; Hendon et al. (2020), Matter – https://doi.org/10.1016/j.matt.2019.12.019

The portafilter

In a portafilter system, freshly ground coffee is dosed into a removable metal basket, distributed evenly and pressed with a tamper into a flat puck. Hot water is then driven through it under pressure. Dose, grind, distribution, tamping, temperature, pressure history and beverage yield all influence the result. The system offers considerable flexibility but calls for careful coordination of grinder, coffee and machine. The preceding article explains how puck structure and channeling are affected by preparation.

Sources: Hendon et al. (2020), Matter, 2, 631–648 – https://doi.org/10.1016/j.matt.2019.12.019

Espresso — definition and physics

Espresso is a preparation method, not a type of coffee bean. Hot water is driven under pressure through a compact bed of finely ground coffee, creating a concentrated drink with intense aromas and often a characteristic crema. A traditional single espresso is roughly 25–30 ml including crema. For repeatable recipes, yield is often measured in grams because foam changes the apparent volume.

Many espresso recipes use brewing pressure around nine bar, but this is neither a universal physical constant nor the only possible profile. Modern machines may include pre-infusion and variable pressure or flow. Dose, grind, temperature, permeability, flow and target yield all contribute. The article on pre-infusion and pressure profiling explores this further.

The five Ms of Italian espresso

The Italian tradition often summarises successful espresso preparation through five terms beginning with M. They are not a fixed numerical recipe but an expression of the interaction among coffee, equipment and skill.

Miscela — the coffee or blend: origin, selection, roasting, composition and freshness determine the drink's potential.

Macinatura — the grind: particle size and distribution, together with dose, affect resistance, brewing time and extraction.

Macchina — the espresso machine: thermal stability, pressure, water delivery and design support repeatable preparation.

Mano — the human hand: skill in calibration, dosing, distribution and preparation makes consistent results possible.

Manutenzione — cleaning and maintenance: water quality, machine hygiene and grinder care prevent avoidable faults. Some traditions call the second M “Macinadosatore” (grinder-doser), but the basic idea is the same.

Why espresso is a multiphase system

Espresso is more than coffee substances dissolved in water. Its aqueous solution contains caffeine, organic acids and other soluble compounds. Tiny droplets of coffee oil form an oil-in-water emulsion. Microscopic solid particles may remain suspended in the drink. In addition, gases—particularly CO₂ released from roasted coffee as pressure falls—form bubbles which, stabilised by components of the liquid, create crema.

The conventional description of espresso as a multiphase drink should not be confused with separate visible strata in the cup. Dissolved substances form a solution, oil droplets form an emulsion and fine particles form a suspension; at the surface, the crema is a foam whose gas bubbles interact with liquid films and surface-active components. The relative contribution of these dispersed phases helps shape the special texture of espresso.

Thus gas, liquid and solid matter coexist in the cup. The terms solution, emulsion and suspension describe how constituents are distributed, not three physical layers. Their interaction influences aroma release, texture and mouthfeel, distinguishing espresso from many paper-filtered brews that retain much of the oil and suspended material.

Sources: Neglected Food Bubbles: The Espresso Coffee Foam, Food Biophysics (2011) – https://pmc.ncbi.nlm.nih.gov/articles/PMC3140933/; Investigation of the factors that affect the volume and stability of espresso crema, Food Research International (2019) – https://www.sciencedirect.com/science/article/pii/S0963996918307105; Influence of Flow Rate, Particle Size, and Temperature on Espresso Extraction Kinetics (2023) – https://pmc.ncbi.nlm.nih.gov/articles/PMC10418593/

Pre-infusion and pressure profiles — espresso under changing pressure

Espresso is often associated with a constant brewing pressure of about nine bar. In reality, extraction depends not just on the pressure reached but on when it is applied and how water flows through the grounds over time. Some machines keep the main phase close to constant pressure; others deliberately vary it. This is pressure profiling.

Pre-infusion — wetting the coffee bed first

During pre-infusion, the grounds are initially wetted before full brewing pressure is applied. This may occur at lower pressure or flow, or through a short wetting stage followed by a pause. The goal is controlled hydration while particles absorb water and the bed changes. Pre-infusion may encourage more even extraction but cannot guarantee that channeling will be avoided.

Constant pressure and variable profiles

Traditional profiles aim for broadly stable pressure after ramp-up. Other profiles may begin gently, rise and then fall again towards the end. In doing so, the machine changes the driving force for water flow. The most suitable shape depends on coffee, grind, dose, basket and intended yield.

Pressure is not the same as flow

Pressure is the driving force per unit area; flow rate describes the volume of water passing in a given time. They are linked through the resistance of the coffee bed. Wetting, swelling, particle movement and dissolution change that resistance during the shot. Nine bar need not give identical flow at every moment. In flow profiling, the machine controls delivered water more directly and pressure responds to the puck.

Higher pressure is not necessarily better, nor does a complex profile automatically yield better espresso. Profiles are tools whose value depends on grind, distribution, tamping, temperature and the taste achieved.

Sources: Influence of Flow Rate, Particle Size, and Temperature on Espresso Extraction Kinetics (2023) – https://pmc.ncbi.nlm.nih.gov/articles/PMC10418593/; Hendon et al. (2020), Systematically Improving Espresso, Matter – https://doi.org/10.1016/j.matt.2019.12.019; espresso puck and flow dynamics: https://arxiv.org/abs/2512.21528

Ristretto, lungo and doppio — what the terms mean

Ristretto, espresso and lungo belong to the same family of pressure-brewed drinks. A ristretto uses a shorter yield, while a lungo passes more water through the coffee bed. A doppio uses a correspondingly larger coffee dose. Typical cup volumes offer guidance but are not universally binding rules.

As rough reference points, a ristretto is around 15–20 ml, a single espresso 25–30 ml, a lungo 45–60 ml and a doppio 50–60 ml. A café crème typically measures about 110–150 ml. Common serving ranges for milk drinks are approximately 150–180 ml for cappuccino, 150–200 ml for flat white and 200–300 ml for caffè latte. Crema affects apparent volume, so weight in grams is usually more precise for technical espresso recipes.

Drink	Typical beverage volume
Ristretto	15–20 ml
Espresso	25–30 ml
Lungo	45–60 ml
Doppio	50–60 ml
Café Crème	110–150 ml
Americano	120–200 ml
Cappuccino	150–180 ml
Flat White	150–200 ml
Caffè Latte	200–300 ml

An Americano is an already extracted espresso diluted with hot water. It is not the same as a lungo, in which more water passes through the grounds. Café crème follows a separate Swiss brewing tradition explained in the next article.

A greater beverage volume affects not only concentration but sometimes which substances are extracted. A lungo may therefore taste different from an espresso diluted to the same final volume. Perceived mildness or bitterness depends on the recipe rather than the name alone.

Sources: study of ristretto, espresso and lungo (2023): https://pmc.ncbi.nlm.nih.gov/articles/PMC10418593/; Istituto Nazionale Espresso Italiano, technical guidelines: https://www.espressoitaliano.org/files/File/istituzionale_inei_hq_en.pdf; Procafé (Swiss Coffee Association), Café Crème: https://www.procafe.ch/fr/portfolio/cafe-creme/; ZURIGA, drink recipes: https://support.zuriga.com/hc/de/articles/4480139164561-Rezepte-Kaffeegetr%C3%A4nke

Café crème — Swiss coffee brewed under pressure

Café crème, also called “Schümli” in Switzerland, is a distinct brewing tradition. Hot water, often delivered by a fully automatic coffee machine, passes under pressure through ground coffee. The drink commonly fills about 110–150 ml and carries a fine golden-brown foam.

The word “crème” does not mean cream must be added. Milk or coffee cream may be served separately, but the distinguishing features are the brewing recipe and beverage volume. The foam resembles espresso crema, though its quantity and stability can differ.

A different recipe from espresso

Dose, grind, water volume and flow are adjusted for a longer drink; the grind is often somewhat coarser than for a short espresso. This lets more water pass through the bed in a suitable time while aiming for balance.

Café crème, lungo and Americano

A lungo pushes more water through an espresso puck; an Americano dilutes a finished espresso. Café crème is brewed from the outset according to a recipe designed for its larger volume, and may therefore taste quite different. The Swiss coffee association Procafé offers an example of about 9 g ground coffee and 120–130 ml water, while cafés use varying recipes.

Sources: Procafé, Café Crème / Schümli: https://www.procafe.ch/fr/portfolio/cafe-creme/; Café crème, Swiss tradition and technique, Kaffeewissen (2017): https://ub-sachdokpdf.ub.unibas.ch/sachdok/2017/BAU_1_001497885_4_2017.pdf; KaffeeWerkStadt Zürich, preparation guidelines: https://kaffeewerkstadt.ch/faqs/wie-ist-ein-ristretto-espresso-cappuccino-cafe-creme-definiert-richtwert/

Hario V60

The Hario V60 is a cone-shaped hand filter with an angle of 60 degrees. Spiral ribs create space between the filter paper and walls, while a comparatively large hole at the bottom allows brewed coffee to drain. Hario introduced the V60 in the mid-2000s.

The brewer controls dose, grind, temperature, speed and distribution of the water. Small differences may alter drawdown time and sensory balance, making the method particularly appealing to experimenters. Start with a consistent brew ratio and alter just one variable at a time.

Sources: Hario, manufacturer description and product history: https://www.hario-europe.com/pages/about; Hario, design of the V60: https://www.hariokitchen.eu/pages/about-the-v60

The moka pot — an Italian classic

The Moka Express, designed by Alfonso Bialetti in 1933, became a celebrated object of Italian kitchen culture. Heating creates pressure in the lower chamber, pushing water through coffee held in a funnel-shaped basket and into the upper chamber.

Its pressure is much lower than that of a typical espresso machine and changes during brewing, as do water temperature and flow. The result is not technically espresso but a distinct, often intense coffee. Flavour depends on the grounds, grind, water level, burner power and when the pot is removed from the heat.

The lower chamber should be filled only to the manufacturer's mark or below the safety valve. Coffee should be added evenly but loosely: do not tamp it into a dense espresso-like puck because the moka is not designed for that resistance. Excess heat near the end can produce unpleasant notes. Clean the pot as instructed and regularly check its gasket and safety valve.

Sources: Museum of Modern Art, Moka Express, Alfonso Bialetti, 1933: https://www.moma.org/collection/works/118645

Turkish coffee and the cezve

Turkish coffee names a preparation method rather than a bean variety or necessarily a Turkish origin. Beans are ground extremely finely, almost to powder. Grounds, water and optionally sugar are combined in a small long-handled pot called a cezve or ibrik. The mixture is heated slowly until characteristic foam rises; prolonged vigorous boiling is generally avoided.

Unlike filter methods, grounds are not removed through paper or a metal filter. The drink is poured into small cups, often about 60–90 ml, and the finest particles settle at the bottom. It is traditionally sipped without disturbing the sediment. Finely ground coffee, gradual heating and foam contribute to its characteristic body and texture.

The method is deeply rooted in the social culture of Turkey and neighbouring regions, where hospitality, conversation and customary serving rituals matter as much as the recipe. UNESCO has recognised Turkish coffee culture and tradition as intangible cultural heritage.

Sources: UNESCO, Turkish Coffee Culture and Tradition (2013) – https://ich.unesco.org/en/RL/turkish-coffee-culture-and-tradition-00645; Türk Kahvesi, EU application for protected geographical indication (2025), preparation and cup-volume information – https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52025XC05912

Paper coffee portions — construction, extraction and aroma protection

A paper coffee portion contains a pre-measured quantity of ground coffee enclosed between filter-paper layers. The portion is placed in a compatible brewing device, where water passes through the paper and compacted grounds. Size, shape, coffee dose, puck thickness and machine design influence extraction and compatibility. Paper portions are not necessarily interchangeable between different systems.

The paper performs a filtering and handling function, but it does not provide an airtight barrier. Grounds have a large exposed area and are sensitive to oxygen, moisture and volatile aroma loss. For this reason, portions normally require a separate protective wrapper until use. Different systems use different doses and geometries, which belong in their respective technical descriptions.

Sources: Consorzio E.S.E., technical standard – https://eseconsortium.com/en/standard; general principles of ground-coffee extraction – https://doi.org/10.1016/j.matt.2019.12.019; Smrke et al. (2022), aroma and storage after opening – https://doi.org/10.1016/j.fpsl.2022.100893.

The E.S.E. standard — espresso in paper pods

E.S.E. stands for Easy Serving Espresso and describes an open technical standard for pre-portioned espresso in filter paper. A typical E.S.E. pod contains about 7 g of ground coffee and has a nominal diameter of 44 mm. The specification is intended to promote compatibility between appropriately certified portions and machines.

The coffee is ground, measured and compacted during manufacture. Users insert the pod in the compatible holder, without having to grind, dose or tamp. Brewing quality still depends on coffee freshness, manufacturing consistency, machine temperature and pressure, and the water supplied.

The paper pod itself is not an oxygen-proof package: protective outer wrapping plays a separate role. E.S.E. does not imply that all other paper-pod designs have the same dose, thickness or compatibility.

Sources: Consorzio E.S.E., official industry standard: https://eseconsortium.com/en/standard

The Reniala System — espresso with paper portions

The Reniala System is a distinct portioned-coffee system combining a specifically engineered paper portion with compatible brewing equipment. Although it also uses filter paper, it is not identical to E.S.E.; machine and portion must be matched to the system's technical requirements.

Portion and compatibility

Reniala portions contain 10 g of ground coffee. Their nominal diameter is 44 mm, but the greater dose produces a differently dimensioned coffee bed from a typical 7 g E.S.E. pod. Sharing a nominal diameter does not establish interchangeability. Geometry, hydraulic behaviour and the brewing holder are decisive.

The R1 — machine and operation

The R1 is designed for Reniala portions and is handcrafted in Italy. It combines stainless steel, die-cast aluminium and selected wood details with a patented portafilter mechanism allowing used portions to be ejected automatically. The system offers selectable beverage intensities, configurable temperature and volume, and maintenance functions. These are system-specific characteristics, not generic properties of all paper-pod machines.

Different coffees, one system

Amici Caffè, L'Arbre à Café and Caffè Bonacchi offer coffees for the Reniala System under their own identities. The shared interface does not mean that the coffee blends, roast approaches and sensory styles must be the same. They remain distinct coffee propositions designed for compatible equipment.

Why the portion needs protective packaging

The paper filters water during extraction but cannot seal out oxygen and moisture. Because the coffee is already ground, the outer protective wrapper matters particularly for preserving its aroma until the moment of brewing. The two packaging functions must not be confused.

Sources: Reniala R1, technical specifications and system description – https://campaign.amici.ch/r1/; Amici, Reniala R1 – https://www.amici.ch/de/kaffeemaschinen-fuer-das-system-ten/876-pre-order.html; L’Arbre à Café, Reniala System and own-brand coffee portions – https://www.larbreacafe.com/pages/reniala-system; Consorzio E.S.E., technical standard for comparison – https://eseconsortium.com/en/standard; additional information on Caffè Bonacchi's participation in the system, as provided by Amici.

How to taste coffee — aroma, flavour and mouthfeel

Tasting coffee is a way of observing several sensations that develop over time. Smell, basic tastes, texture and aftertaste together create the impression of a cup. A structured tasting does not mean hunting for the “correct” list of flavour notes; it means paying attention and learning to describe sensations consistently.

First impression — begin with the nose

Before drinking, smell the freshly prepared coffee. The aromatic compounds travelling through the nose may suggest fruit, nuts, chocolate, flowers, spices or other associations. The same coffee can smell different as temperature changes.

The first sip — separate taste from texture

Basic taste sensations include sweetness, sourness and bitterness. At the same time, the tongue and mouth sense temperature, weight, creaminess and drying sensations. Body describes texture and mouthfeel rather than a basic taste; astringency is the rough or puckering feeling, not another primary taste.

Aromas in the mouth — beyond the tongue

Much of what people casually call taste is actually retronasal smell: during drinking and exhaling, volatile compounds travel from the mouth towards the nose. Coffee may therefore smell different above the cup and during swallowing. Both experiences are part of an informed evaluation.

Aftertaste and changing temperature

After swallowing, observe how long sensations remain and whether the finish is sweet, fruity, chocolate-like, harshly bitter or drying. As coffee cools, some volatile notes become less apparent while other tastes and textures emerge. Tasting at more than one temperature can be revealing.

Compare deliberately

Start with two coffees, or two preparations of the same coffee. Smell first, taste in small sips, observe mouthfeel and finish, then compare again after cooling. Separate your notes into aroma, sweetness, acidity, bitterness, body, astringency and aftertaste. The Coffee Taster's Flavor Wheel helps find precise aroma language; formal cupping provides a controlled framework for comparison.

Sources: ISO 18794:2025, Coffee – Sensory analysis – Vocabulary – https://www.iso.org/obp/ui?_escaped_fragment_=iso%3Astd%3Aiso%3A18794%3Aed-2%3Av1%3Aen; World Coffee Research, Sensory Lexicon – https://worldcoffeeresearch.org/; Specialty Coffee Association, Coffee Value Assessment – https://sca.coffee/value-assessment/; Specialty Coffee Association, Coffee Taster’s Flavor Wheel – https://sca.coffee/store/flavor-wheel

The Coffee Taster's Flavor Wheel

The Coffee Taster's Flavor Wheel is a shared vocabulary for describing coffee. The Specialty Coffee Association revised it with World Coffee Research in 2016. Sensory impressions are arranged from broad families to increasingly specific descriptions. Terms such as citrus, cocoa or jasmine describe perceptions and associations; they do not mean those ingredients were added. The wheel primarily addresses aroma. Taste, body and astringency must also be evaluated, as explained in the article on tasting.

Sources: Specialty Coffee Association – Coffee Taster’s Flavor Wheel – https://sca.coffee/store/flavor-wheel

Sweetness, bitterness, body, astringency and finish

Sweetness, bitterness, body and aftertaste are central dimensions of coffee. Sensory sweetness does not simply mean the measured sugar content of the prepared drink. Bitterness can be pleasant or distracting depending on intensity and context. Body describes mouthfeel, influenced by dissolved and suspended substances. The finish refers to sensations that persist after swallowing; personal preference contributes to their evaluation.

Astringency — when the mouth feels dry

Astringency is not a basic taste such as sweet, sour or bitter. It is more of a tactile sensation: the mouth feels dry, rough or slightly contracted, rather like after very strong black tea or unripe fruit. It may persist after swallowing.

One explanation is that certain phenolic compounds and other molecules interact with proteins in saliva, reducing lubrication and creating the sensation of dryness. The mechanisms are complex; bitterness does not necessarily coincide with astringency. Strong astringency may arise from problematic raw material or unbalanced brewing.

It is therefore useful to ask whether a coffee is merely intense and bitter or also leaves the mouth feeling puckered. Full body is not the same as astringency: an espresso can be rich and velvety without feeling dry.

Sources: ISO 18794:2025, Coffee – Sensory analysis – Vocabulary, terminology for mouthfeel and astringency – https://www.iso.org/obp/ui?_escaped_fragment_=iso%3Astd%3Aiso%3A18794%3Aed-2%3Av1%3Aen; Chemical characterization and sensory evaluation of a phenolic-rich melanoidin isolate contributing to coffee astringency, Food & Function (2025) – https://doi.org/10.1039/D4FO04934A; Specialty Coffee Association, Coffee Value Assessment – https://sca.coffee/value-assessment/

Acidity — coffee's liveliness

Acidity in coffee describes a sensory sensation as well as a measurable chemical property. Balanced acidity can make a cup feel lively, juicy or fresh, much like certain fruits or wines.

It may suggest citrus, green apple or ripe berries. Such comparisons describe perception rather than identifying one chemical acid responsible for a note. Whether acidity is pleasant depends on sweetness, bitterness, body and aroma, and on roasting, processing and extraction. “Low acid” does not inherently mean better coffee, and “sour” is not necessarily a defect.

Sources: World Coffee Research, Sensory Lexicon: https://worldcoffeeresearch.org/read-more/news/174-world-coffee-research-sensory-lexicon; Williams et al. (2023), characterisation of acidity, mouthfeel and finish: https://doi.org/10.1111/joss.12886

Caffeine — the molecule

Caffeine is a naturally occurring constituent of coffee. It increases alertness in part by blocking the effects of the signalling substance adenosine at certain receptors. Its effect and duration vary considerably between individuals. Timing matters too: caffeine can interfere with sleep.

Sources: EFSA NDA Panel (2015), EFSA Journal 13(5):4102 – https://doi.org/10.2903/j.efsa.2015.4102

How much caffeine is in a cup?

Caffeine content depends on the coffee species, dose and preparation. The words “espresso”, “lungo” or “filter coffee” alone do not specify a reliable fixed dose of caffeine.

Robusta generally contains substantially more caffeine per unit dry mass than Arabica. Using equal amounts of 100% Arabica and 100% Robusta with the same method therefore normally yields more caffeine in the Robusta cup. Twice as much caffeine in the bean does not necessarily translate into exactly twice the dose in every drink because extraction varies.

As an orientation, the European Food Safety Authority (EFSA) cites roughly 80 mg for a 60 ml espresso and 90 mg for a 200 ml filter coffee. These are examples, not guarantees for individual drinks.

For healthy adults EFSA regards single intakes up to 200 mg and a total of up to 400 mg per day from all sources as generally not raising safety concerns. During pregnancy the indicated daily maximum is 200 mg. Individual sensitivity varies, and smaller doses can still affect sleep.

Sources: EFSA, scientific opinion on caffeine (2015): https://www.efsa.europa.eu/de/topics/topic/caffeine; Caffeine Consumption through Coffee (2019), Beverages 5(2), 37 – https://doi.org/10.3390/beverages5020037

Decaffeination — how caffeine is removed

Decaffeination normally removes caffeine from green beans before roasting. The aim is to dissolve and extract caffeine while preserving as many other coffee constituents as possible.

Methods include water and activated-carbon processes, pressurised carbon-dioxide extraction, and the use of approved solvents such as ethyl acetate or dichloromethane. They differ technically, and no method name alone guarantees a superior flavour outcome.

Decaffeinated coffee is not completely caffeine-free. Under Swiss requirements, coffee marketed as decaffeinated may contain no more than 0.1% caffeine by dry weight after roasting. The residual caffeine reaching a cup also depends on brewing.

Sources: Specialty Coffee Association, Chemistry of Decaf: https://sca.coffee/sca-news/coffee-decoded-21-chemistry-of-decaf; Canton of Zurich, information on decaffeinated coffee and residual caffeine: https://www.zh.ch/de/gesundheit/lebensmittel-gebrauchsgegenstaende/lebensmittel/umgang-lebensmittel.html

Ethiopia — the origins

Coffee's history begins long before coffeehouses. The wild ancestors of Arabica originate in present-day Ethiopia, whose south-western mountain forests still contain exceptional genetic diversity. They are an important part of the natural heritage of the coffee plant.

Exactly how people discovered coffee's stimulating effect is unknown. The famous tale of Kaldi, the goat herder who noticed unusual energy in his animals after they ate coffee cherries, is a legend recorded many centuries after the presumed beginnings of coffee consumption.

Coffee's importance in Ethiopian culture, however, is beyond doubt. During the traditional coffee ceremony, beans are roasted, ground and brewed in a rounded pot called a jebena. Sharing the beverage expresses hospitality and creates time for conversation. Coffee here is not simply a drink but time spent together.

Sources: UNESCO, Ethiopia, the home of coffee (2023): https://www.unesco.org/en/articles/ethiopia-home-coffee

Yemen, the Sufis and Mocha

As a regularly prepared drink, coffee is particularly closely associated with Yemen. By the fifteenth century, consumption had spread there, including among Sufi religious communities, whose night prayers and ceremonies benefited from its stimulating properties.

Trade and pilgrimage routes took the drink through the Arabian Peninsula, North Africa and the Ottoman world. Coffee was more than a commodity: it brought people together and sometimes provoked disputes about its acceptability and the places in which it could be consumed.

“Mocha” recalls al-Mukha, the Yemeni port on the Red Sea that became associated with historic coffee trade. Its commercial activities were more diverse than later coffee legends sometimes suggest. The word is both a geographical name and a piece of trading history, long before it came to describe different coffee beverages in Europe.

Sources: British Museum, Life in a Cup – Coffee Culture in the Islamic World: https://www.britishmuseum.org/exhibitions/life-cup-coffee-culture-islamic-world; UNESCO, Ethiopia, the home of coffee: https://www.unesco.org/en/articles/ethiopia-home-coffee; C. G. Brouwer (2008), Itinerario, research on trade through al-Mukha: https://doi.org/10.1017/S0165115300001972

Coffeehouses — Istanbul, Venice, London and Vienna

Coffeehouses became places of conversation, trade and public debate. A vibrant café culture developed in sixteenth-century Istanbul and later spread to European cities, each of which gave it its own character.

Caffè Florian opened in Venice's St Mark's Square in 1720 and still operates. In London, merchants and shipowners exchanged news and negotiated business in specialised coffeehouses. Edward Lloyd's establishment, documented by 1688, eventually gave rise to the Lloyd's insurance market.

Vienna developed another distinctive café institution, with newspapers, small marble tables and guests lingering for hours. The familiar story that Georg Franz Kolschitzky founded the first Viennese café after the siege of 1683 is legendary; historical accounts instead identify the Armenian Johannes Diodato as an early key figure. Viennese coffeehouse culture has been listed in Austria's national inventory of intangible cultural heritage since 2011.

What these places share is not simply the beverage but the opportunity to participate in public life for the price of a cup. A further transformation took place in twentieth-century Italy: the rise of espresso made quick coffee “al banco”, standing at the bar, a daily ritual. Machines and counters became focal points of bar architecture and reflected the tempo of urban working life without eliminating coffee's social role.

Sources: British Museum, Life in a Cup: https://www.britishmuseum.org/exhibitions/life-cup-coffee-culture-islamic-world; Caffè Florian, history: https://caffeflorian.com/en/florian-venezia/history/; Lloyd’s, Coffee and Commerce: https://www.lloyds.com/about-lloyds/history/coffee-and-commerce; Österreichische UNESCO-Kommission, Wiener Kaffeehauskultur: https://www.unesco.at/kultur/immaterielles-kulturerbe/verzeichnis/element/wiener-kaffeehauskultur; Baldioli (2006), L’espresso. Modernità e tradizione nell’Italia del caffè; E. V. L. Illy (2011), The Evolution of American Coffee Consumption, ch. 2.4 (master’s thesis, historical secondary analysis)

The invention of espresso

Espresso was not invented on a single day. It emerged through successive attempts to brew coffee fresh, immediately before serving. Angelo Moriondo patented an early steam-driven coffee machine in Turin in 1884. Luigi Bezzera developed single-serving machines around 1901, and Desiderio Pavoni helped spread them in Italian bars from 1905 onwards.

An important advance arrived in Trieste in 1935 with Francesco Illy's Illetta. Early espresso machines used steam pressure to drive hot water through the grounds; Illetta used compressed air instead. This separated the pressure needed for extraction from the heating of the water, improving control and helping avoid excessive coffee temperatures. Illetta is therefore an important precursor of modern espresso machines.

Achille Gaggia subsequently developed a spring-assisted lever mechanism, patented in 1947, which enabled higher brewing pressures and helped establish the characteristic crema of post-war espresso. Illy's compressed-air design and Gaggia's lever were distinct technical solutions to the same challenge.

Faema's E61, introduced in 1961, used an electrically powered pump to generate brewing pressure independently of the barista's arm. Espresso remains a meeting of engineering and craft: grind, dose, temperature and beverage yield still shape every cup. Its story is also a chapter in Italian industrial and everyday history.

Sources: Jonathan Morris, Making Italian Espresso, Making Espresso Italian, Food and History 8(2), 2010, DOI: 10.1484/J.FOOD.1.102222; Università Cattolica, CERSI, Illy case study (2009), table of innovations: https://centridiricerca.unicatt.it/cersi-CERSI_CCA_4_2009_Illy%281%29.PDF

From the Italian espresso bar to the American coffee shop

The Italian espresso bar and the American coffee shop are closely linked but are not identical. In Italy, espresso became a brief daily ritual during the twentieth century: a freshly prepared drink at the counter and often a short social encounter.

After World War II, industrially processed coffee for home use dominated much of the US market. From the 1960s a smaller movement began to rediscover whole beans, fresher roasting and specific origins. Alfred Peet opened a store in Berkeley in 1966, teaching customers about beans, roasting and preparation as well as selling coffee. Starbucks's founders initially adopted a similar retail-bean model when they opened in Seattle in 1971.

The Italian café culture supplied a subsequent turning point. Howard Schultz experienced Milan's espresso bars in the early 1980s and was impressed by their combination of drink, service, atmosphere and everyday sociability. He opened the Italian-inspired Il Giornale in 1986 and, with partners, acquired the Starbucks business in 1987, carrying forward that name.

The business model shifted: alongside coffee as a product, the coffee shop became an experience. National and then international chains introduced espresso beverages to broader audiences, using standardised procedures for consistency and speed. This also raised questions about craftsmanship, individual character and scale. The Third Wave would later emphasise coffee's agricultural identity and the people and processes behind it.

Sources: E. V. L. Illy (2011), The Evolution of American Coffee Consumption, master’s thesis, ch. 2.4, 3.3, 4.2–4.3 and 5; with additional references in Nancy F. Koehn (2005), Howard Schultz and Starbucks Coffee Company; Bryant Simon (2009), Everything but the Coffee; Mark Pendergrast (2010), Uncommon Grounds. Additional sources: Peet’s, company history – https://www.peets.com/pages/timeline

The three waves of coffee

The expression “three waves” is a way of describing broad changes in modern coffee culture, particularly in the United States. It is a useful framework, not a precise chronology that applies everywhere. Different approaches coexist, and no wave automatically replaces what came before.

The first wave broadly describes the mass-market expansion of coffee into everyday domestic consumption. Industrial roasting, packaged ground coffee, advertising, supermarket distribution and instant products made it widely available. Coffee was often marketed primarily for convenience, price and the stimulating function of caffeine.

The second wave placed increasing emphasis on coffeehouses, espresso-based drinks and the café experience. The specialty movement predates large chains: Alfred Peet's Berkeley store opened in 1966, and Starbucks began in 1971 as a seller of whole-bean coffee. Howard Schultz subsequently drew on Italian espresso-bar culture, with growing chains transforming coffee consumption into a widely accessible social ritual.

The third wave strengthened attention to the coffee itself as an agricultural and crafted product. Origin, variety, processing, traceability, roasting and carefully controlled brewing became more visible. Independent cafés, small roasters, direct relationships and single-origin coffees gained prominence. Coffee tasting increasingly borrowed the vocabulary and comparative attention familiar from wine.

These changes reflect more than a linear improvement in taste. Coffee can signify craftsmanship, authenticity, status, belonging or ethical concern. Sociological interpretations have examined how consumption communicates identity as well as pleasure, but such interpretations should not be mistaken for proof of any individual's motivation. Consumers differ widely in what they know, value and enjoy.

The framework has limits: Italian café culture evolved along a different timeline, traditional blends remain important, and innovative equipment may combine specialty values with convenience. What has changed most is the range of meanings attached to a cup, from everyday fuel to a product whose origin and preparation invite scrutiny.

Sources: E. V. L. Illy (2011), The Evolution of American Coffee Consumption, master’s thesis, particularly ch. 3–6 (historical analysis, as of 2011); drawing on Nancy F. Koehn (2005), Howard Schultz and Starbucks Coffee Company; Bryant Simon (2009), Everything but the Coffee; Thorstein Veblen (1899/2007), The Theory of the Leisure Class (interpretive framework). Additional sources: UC Davis Library, Second Wave – https://library.ucdavis.edu/exhibit/brewed-awakening/second-wave/; Peet’s, chronicle – https://www.peets.com/pages/timeline; Los Angeles Times (2019), Trish Rothgeb and the term «Third Wave» – https://www.latimes.com/food/story/2019-10-04/third-wave-coffee-trish-rothgeb

Coffee in art and thought

Coffee has accompanied writers, artists, musicians and political thinkers for centuries. Coffeehouses offered settings for discussion, reading, commerce and the exchange of ideas. Their openness varied greatly by city and era, yet they helped create new forms of social interaction outside the home.

Coffee appears in literature and visual art as a symbol of hospitality, wakefulness, urban life and intellectual exchange. Design also shaped the experience: the layout of a café, the elegance of a cup and the appearance of a brewing machine can become part of the ritual. Coffee culture is therefore not only the history of an ingredient but also of the spaces, objects and relationships surrounding it.

Sources: Netherlands Bach Society, Kaffeekantate BWV 211: https://www.bachvereniging.nl/en/bwv/bwv-211; Metropolitan Museum of Art, Manet/Degas, Visiting Guide: https://www.metmuseum.org/de/exhibitions/manet-degas/visiting-guide

What certification labels mean — and what they do not

With coffee, three questions should be kept separate. How is it traded? How are growers and workers treated and remunerated? How is the environment protected in the producing area? Direct Trade concerns commercial relationships rather than a uniform certification. Fairtrade and Rainforest Alliance both address economic, social and environmental requirements through different systems. Organic and Demeter primarily specify agricultural production practices.

Fairtrade International combines requirements with a minimum-price safety net and a separate premium for the producers' organisation. Rainforest Alliance has no comparable universal minimum price for coffee, but uses independent environmental and social requirements together with a negotiated premium. Fairtrade also has environmental rules; Rainforest Alliance is not purely an environmental label.

Certification does not necessarily cover an entire brand, every coffee or all of a company's farms. Claims should identify which producer, chain and product are covered by valid certificates. Conversely, absence of a label proves neither good nor poor farming: it mainly means that this formal verification is absent. A logo alone cannot guarantee how a cup tastes.

Sources: Fairtrade International – https://www.fairtrade.net/ch-de/was-ist-fairtrade/fairtrade-ansatz/standards/mindestpreise-praemien.html; Rainforest Alliance, Premium Annex v1.4 – https://knowledge.rainforest-alliance.org/docs/premium-annex-v14; European Commission, organic farming law – https://agriculture.ec.europa.eu/farming/organic-farming/legislation_en; Demeter International, Standard 2026 – https://demeter.net/certification/standard/.

Fairtrade and Rainforest Alliance — different approaches to responsibility

Fairtrade and Rainforest Alliance are certification systems, not trading companies buying all coffee themselves. Both set requirements for producers and other participants, and both consider social and environmental matters. Their economic instruments and priorities differ.

Fairtrade — a price safety net and a collective premium

The Fairtrade International minimum coffee price is a safety net. When the relevant market price is higher, the higher price normally applies, and additional quality premiums may be negotiated. In October 2026 the minimum for washed Arabica is US$1.80 per pound of green coffee, rising to US$2.00 on 1 December 2026. The separate Fairtrade Premium is US$0.20 per pound; eligible organic coffee attracts an additional differential.

Fairtrade coffee is predominantly certified through organised small-producer groups. The separate premium is paid to the producers' organisation, whose members make democratic decisions about its use. This is not the same as distributing every dollar directly to each farmer. Investments in equipment, training or shared infrastructure may nevertheless benefit farmers substantially.

Minimum prices and quality incentives

A floor price limits some downside risk but does not replace individual quality pricing. Economic research suggests that, under particular market conditions, a uniform price floor across heterogeneous qualities may influence where growers sell different lots. Exceptional coffees may attract stronger quality premiums elsewhere. This is a possible incentive mechanism, not evidence that Fairtrade coffee is inherently lower in quality or necessarily more inconsistent. Fairtrade rules explicitly allow negotiated quality differentials.

Rainforest Alliance — certified practices with a negotiated premium

Rainforest Alliance sets standards for farming and supply chains covering environmental protection, ecosystems, labour and risk management. It does not specify a universal coffee minimum price. Buyers and sellers negotiate prices and quality differentials, while an additional sustainability premium is agreed and documented separately. Under provisions introduced in 2026, certified producer groups generally must distribute at least 40% of the monetary premium received to their members; this is separate from the raw-coffee purchase price.

Rainforest Alliance and Direct Trade can therefore coexist: a roaster may negotiate personally with growers while purchasing independently certified coffee, or buy certified coffee through an importer.

Choosing a system

Neither label guarantees the flavour of a given lot, the unchanged taste of a blend over time or a living income on every farm. Those outcomes depend on actual prices, quality requirements, transparent payments and local circumstances in addition to audits.

Sources: Fairtrade International, minimum prices and premiums (2026) – https://www.fairtrade.net/ch-de/mach-mit/news/neue-mindestpreise-fuer-fairtrade-kaffee.html; Fairtrade International, rules and quality differentials – https://riskmap.fairtrade.net/salient-issues/living-income; Rainforest Alliance, Premium Annex v1.4 – https://knowledge.rainforest-alliance.org/docs/premium-annex-v14; Rainforest Alliance, Shared Responsibility – https://knowledge.rainforest-alliance.org/docs/race-to-the-top-our-new-approach-to-shared-responsibility; de Janvry, McIntosh & Sadoulet (2010), Fair Trade and Free Entry – https://gspp.berkeley.edu/research-and-impact/working-papers/fair-trade-and-free-entry-the-dissipation-of-producer-benefits-in-a-disequi.

Organic and Demeter — two agricultural standards

While Direct Trade describes commercial relationships and Fairtrade and Rainforest Alliance cover different requirements along the supply chain, organic and Demeter standards primarily concern cultivation. Categories may overlap: a coffee may be organically grown, traded directly and also certified under another sustainability programme.

Organic — verified rules for ecological production

In Europe “organic” is a regulated designation subject to inspection. EU Regulation 2018/848 defines requirements for production inputs, natural resources and certification; imports are subject to additional verification. A farm applying organic practices cannot automatically market its output as certified organic without the appropriate accreditation.

Organic certification does not establish a particular purchase price, allocation of trade margins or cup quality. Nor does it reveal the exact level of shade; each of these characteristics requires separate information.

Demeter — biodynamic farming with additional requirements

Demeter is a private standard for biodynamic agriculture built on organic rules, with additional requirements for farm management as a whole and the use of biodynamic preparations. Demeter also includes social requirements, and farms undergo additional checks. Claims that a particular coffee is Demeter-certified must be supported by current farm and supply-chain documentation.

Sources: European Commission, Regulation (EU) 2018/848 and inspections – https://agriculture.ec.europa.eu/farming/organic-farming/legislation_en; https://agriculture.ec.europa.eu/farming/organic-farming/controls_en; Demeter International, International Demeter Biodynamic Standard 2026 and Social Responsibility Standard – https://demeter.net/certification/standard/.