A–C
Acidity — A positive sensory attribute in specialty coffee describing brightness, liveliness, or tartness perceived primarily on the sides and tip of the tongue. Acidity in coffee is produced by organic acids — citric, malic, phosphoric, acetic, quinic, and others — developed during cherry maturation and preserved or altered by processing and roasting. Not to be confused with sourness, which indicates under-extraction or defect. High-quality washed Kenyan and Ethiopian coffees are known for pronounced, complex acidity.
Aftertaste — The flavor sensation that lingers in the mouth after swallowing coffee. Evaluated as a positive attribute on the SCA cupping form. Long, pleasant aftertaste — described as lingering sweetness, fruit, or spice — indicates high-quality extraction of complex flavor compounds. Short, abrupt finish or bitter aftertaste typically indicates defects or over-extraction.
AeroPress — A manually operated brewer invented by Alan Adler (founder of Aerobie) and released in 2005. It uses air pressure to push water through a compact puck of ground coffee, producing a concentrated, clean, rapidly extracted cup. The AeroPress is versatile across grind sizes and recipes, making it suitable for filter-strength recipes and concentrated espresso-style output.
Altitude — Meters above sea level (masl) at which coffee is grown. Higher altitude correlates with cooler temperatures, slower cherry maturation, denser beans, and typically more complex flavor development. Not a guarantee of quality but a meaningful predictor of cup character range. Expressed on bag labels and in green coffee specifications.
Anaerobic fermentation — A processing technique in which coffee cherries or depulped coffee are sealed in oxygen-deprived environments (tanks, sealed bags) during fermentation. The absence of oxygen shifts microbial activity toward lactic acid bacteria and produces distinctive flavor compounds — tropical fruit, wine, and fermented character — not found in aerobic fermentation. A relatively recent technique in specialty coffee, developed from winemaking concepts.
Arabica (Coffea arabica) — One of the two primary commercial coffee species. Allotetraploid (four chromosome sets), originating as a natural hybrid between C. canephora and C. eugenioides in the Ethiopian highlands. Responsible for virtually all specialty coffee. Contains approximately 1.2–1.5% caffeine by dry weight. See also: Robusta.
Astringency — A tactile sensation of dryness or puckering in the mouth, distinct from bitterness, caused by tannins and certain chlorogenic acid degradation products. Not a positive attribute in well-prepared coffee. Often caused by over-extraction, under-ripe cherries, or robusta-heavy blends. Similar to the sensation of unripe fruit or over-steeped black tea.
Body — The physical weight, thickness, or viscosity of coffee perceived in the mouth. A function of dissolved and suspended solids — primarily oils, proteins, and fine particulate. Brewing method significantly affects body: French press produces heavy body; paper-filtered pour-over produces lighter body. Not synonymous with strength; a light-bodied coffee can be highly concentrated.
Bloom — The initial pour of hot water over coffee grounds at the start of a pour-over brew, typically using approximately twice the coffee weight in water. During blooming, CO₂ trapped in freshly roasted beans escapes rapidly, causing the grounds to swell. A 30–45 second bloom allows this degassing to complete before the main pour, promoting more even subsequent extraction.
Burr grinder — A grinder that crushes coffee between two abrasive surfaces (burrs) at a set distance, producing relatively uniform particle sizes. Produces superior grind uniformity compared to blade grinders. Available in conical and flat burr designs; see those entries. Essential for consistent extraction.
Carbonic maceration — A processing technique adapted from winemaking in which whole coffee cherries are placed in CO₂-saturated sealed tanks. The CO₂ environment triggers intracellular fermentation within the intact cherry, producing distinct flavor compounds. Used to develop intense, clean fruity character with low fermentation funk. Distinct from standard anaerobic fermentation by the use of externally introduced CO₂.
Caffeine — An alkaloid compound responsible for coffee’s stimulant effect, produced by the coffee plant as a natural pesticide. Arabica contains approximately 1.2–1.5% by dry weight; Robusta approximately 2.2–2.7%. Caffeine is one of the primary contributors to coffee’s bitterness. Decaffeination processes (Swiss Water, methylene chloride, CO₂ supercritical extraction) remove approximately 97–99.9% of caffeine.
Channeling — An extraction defect in espresso (and to a lesser degree in pour-over) in which water finds a path of least resistance through the coffee puck or bed rather than flowing evenly through all grounds. Results in under-extracted channels coexisting with over-extracted zones, producing an unbalanced cup. Caused by uneven tamping, air gaps, or inconsistent grind distribution. Prevented by leveling, even distribution, and consistent tamping pressure.
Cherry — The ripe fruit of the coffee plant. Consists of the outer skin (exocarp), fruit pulp (mesocarp), mucilage layer, parchment skin, silver skin, and the coffee seeds (beans) at the center. Typically red or yellow when ripe, depending on cultivar. Cherries are harvested and then processed to extract the seeds.
Clean cup — One of the ten attributes on the SCA cupping form. Describes the absence of defects, off-flavors, and interfering impressions in the cup. A clean cup allows the coffee’s origin and processing character to be evaluated without distortion from defect flavors. Clean cup score is binary for each individual cup evaluated.
Cold brew — A brewing method in which coarse-ground coffee is steeped in cold or room-temperature water for 12–24 hours. The long, cold extraction produces a concentrate lower in certain acids than hot-brewed coffee (particularly citric and some volatile acids that require heat to extract efficiently). Cold brew concentrate is typically diluted 1:1 or 1:2 before drinking.
Crema — The reddish-brown emulsified foam layer that forms on the surface of espresso. Composed of CO₂ gas bubbles stabilized by emulsified oils and proteins. Crema indicates freshness (CO₂ is present only in recently roasted coffee), proper extraction pressure (9 bar approximately), and Robusta content (which produces more stable crema than Arabica). Crema dissipates as CO₂ escapes and is not a reliable sole indicator of espresso quality.
Cultivar — A cultivated variety of a plant species, intentionally selected or bred for specific characteristics. In coffee, cultivars include Bourbon, Typica, Caturra, Gesha, Pacamara, SL-28, Ruiru 11, and hundreds of others. Each cultivar has documented flavor tendencies, disease resistance profiles, and yield characteristics. See also: variety.
Cupping — The standardized sensory evaluation protocol used throughout the coffee industry to assess green coffee quality, roast profiles, and production lots. The SCA cupping protocol specifies grind size, water temperature (93°C), coffee-to-water ratio (approximately 1:18.18 by weight), steep time (4 minutes), and a structured evaluation form. Cuppers break the crust formed by grounds at the surface, evaluate aroma, then evaluate flavor, aftertaste, acidity, body, balance, uniformity, clean cup, sweetness, and overall impression.
D–G
Defect — Any fault in green coffee that negatively affects cup quality. The SCA grades defects in two categories: Category 1 (full black, full sour, pod, fungus, foreign matter) and Category 2 (partial black, partial sour, parchment, floater, immature, withered, small stone, small stick, hull). Specialty grade allows zero Category 1 defects and no more than five Category 2 defects per 350g sample.
Degassing — The release of CO₂ from freshly roasted coffee beans. Roasting generates large amounts of CO₂ trapped in the bean’s cellular structure. This gas escapes gradually over days and weeks, with the most vigorous release in the first three to seven days post-roast. Specialty bags use one-way degassing valves to release CO₂ while preventing oxygen ingress. Brewing freshly roasted coffee before degassing is complete can cause uneven extraction due to gas interference.
Direct trade — A sourcing relationship in which a roaster purchases green coffee directly from a producer, mill, or cooperative without a traditional commodity broker intermediary. Direct trade implies relationship-based sourcing, quality-focused pricing, and supply chain transparency, though the term has no formal regulatory definition. Not equivalent to Fair Trade certification.
Dose — The mass of ground coffee used in a brewing recipe, expressed in grams. In espresso, typically 14–21g. In filter coffee, typically 15–25g per cup depending on batch size and ratio. Dose is the first variable set in most recipes and determines the reference point for all other measurements including ratio.
Dry process — See: Natural processing.
Espresso — A concentrated coffee brewing method in which hot water at approximately 9 bar pressure is forced through a compacted puck of finely ground coffee over approximately 25–35 seconds. Produces 25–50ml of liquid with high dissolved solids concentration, full body, and crema. The base for most milk-based café drinks (latte, cappuccino, cortado). Not a roast level — espresso can be made from any roast level, though lighter roasts require technique adjustments.
Extraction — The process by which water dissolves flavor compounds from coffee grounds. Expressed as extraction yield: the percentage of the coffee’s original mass that dissolves into the water. The SCA identifies optimal extraction range as 18–22% for filter coffee. Under-extraction (below 18%) produces sour, thin, underdeveloped cups; over-extraction (above 22%) produces bitter, harsh, dry cups. Grind size, water temperature, contact time, and agitation all affect extraction.
Fermentation — In coffee processing, the enzymatic and microbial breakdown of mucilage and other fruit compounds on the surface of depulped coffee beans. A necessary step in washed processing to remove mucilage, and an inherent part of natural processing as the cherry dries. Fermentation duration, temperature, and microbial environment influence flavor in the final cup. Controlled fermentation is a quality tool; uncontrolled fermentation is a defect source.
Filter coffee — Coffee brewed by percolation through a paper, cloth, or metal filter. Includes pour-over (V60, Chemex, Kalita), drip machines, and Clever Dripper hybrids. Paper-filtered coffee has lower body and lipid content than immersion-brewed coffee. Also used colloquially to distinguish batch-brewed or drip coffee from espresso.
First crack — A physical and audible event during coffee roasting that occurs at approximately 196°C (385°F) when internal steam pressure causes the bean to expand and split. Sounds like popcorn popping. First crack marks the beginning of the light roast range. Specialty light roasts are typically finished shortly after first crack; medium roasts develop further; dark roasts continue toward or through second crack.
Flavor — One of the ten sensory attributes evaluated on the SCA cupping form. Encompasses the primary taste and olfactory characteristics perceived during consumption. Encompasses acidity, sweetness, bitterness, and all aromatic impressions experienced while the coffee is in the mouth.
Fragrance/Aroma — The first attribute evaluated on the SCA cupping form. Fragrance refers to dry ground coffee smell; aroma to the wet grounds or brewed coffee. Evaluated before and after adding hot water during cupping. High-quality coffees show complex, pleasant fragrance; defective coffees may show musty, fermented, or flat fragrance.
Green coffee — Unroasted coffee seeds (beans). The international trade commodity. Green coffee retains flavor potential for twelve to twenty-four months when stored at stable temperature and humidity. Specialty green coffee is evaluated for physical defect count and cupped to assess quality before purchase.
Gesha (also spelled Geisha) — An Arabica cultivar originating from the Gori Gesha forest in southwestern Ethiopia, introduced to Panama through CATIE in Costa Rica. Famously introduced to the specialty market by Hacienda La Esmeralda in Boquete, Panama in 2004, when it sold at auction for a then-record price. Associated with intense jasmine, bergamot, and tropical fruit aromatics of exceptional clarity. Now grown in Colombia, Ethiopia, Costa Rica, and elsewhere. Consistently commands the highest prices in specialty coffee auctions.
Grind size — The particle diameter of ground coffee, typically described in reference to tactile standards (fine, medium-fine, medium, medium-coarse, coarse) or in microns. Grind size determines the surface area of coffee exposed to water, directly controlling extraction rate and drawdown speed in filter brewing. One of the primary adjustment variables for dialing in any brew recipe.
H–M
Honey process — A processing method in which the coffee cherry skin is removed (like washed) but varying amounts of the mucilage layer are left on the parchment before drying. Yellow honey retains the least mucilage; black honey the most. Produces cup character intermediate between washed and natural. Requires careful management to prevent mold during drying.
Immersion brewing — Any brewing method in which coffee grounds are submerged in water for the duration of extraction. Includes French press, AeroPress, Clever Dripper, siphon, and cold brew. Extraction follows a self-limiting concentration gradient that slows as dissolved-solids concentration increases. Generally more forgiving of timing variation than percolation methods.
Latte — Espresso combined with steamed milk, typically in a ratio of approximately 1:3–1:5 espresso to milk, with a small amount of microfoam on top. Not the same as a flat white (smaller volume, different milk texture) or cappuccino (equal parts espresso, steamed milk, and foam by volume). Originally Italian (caffè latte) but now a global café staple.
Malic acid — One of the principal organic acids in coffee, associated with green apple, pear, and crisp apple-like acidity. Found at higher concentrations in high-altitude coffees with slow cherry maturation. Familiar as the primary acid in apple juice.
Microlot — A small, individually traceable coffee lot with specific quality characteristics, typically from a single farm, processing run, or production day. Microlots are sized for quality separation rather than commercial volume and are sold at premiums reflecting their traceability and cup scores.
Mucilage — The sticky, pectin-rich layer surrounding the coffee seed underneath the depulped fruit skin. Mucilage must be broken down (by fermentation or mechanical washing) in washed processing or dries onto the bean in honey and natural processing. The composition of mucilage — primarily pectin, sugars, and water — makes it the primary site of fermentation-derived flavor development.
Mouthfeel — See: Body.
N–R
Natural processing — A processing method in which harvested coffee cherries are dried whole, with all fruit intact, typically on raised beds or patios for three to six weeks. As the cherry desiccates, fruit sugars and fermentation byproducts migrate into the bean, producing distinctive fruity, wine-like, or sweet cup characteristics. Requires careful management to prevent mold and uneven fermentation. The traditional method of Ethiopia, Yemen, and Brazil.
Origin — The geographic source of a coffee, typically specified at country, region, and farm levels. In specialty coffee, origin is considered a primary quality and flavor determinant alongside variety and processing. Single-origin coffee comes from one defined geographic source without blending with other origins.
Parchment — The papery skin that surrounds the green coffee seed after the mucilage is removed. Coffee in parchment is the standard storage and export form for washed coffees. Parchment is removed (hulled) shortly before export. Storing coffee in parchment protects it during the resting period between processing and export.
Percolation — A brewing method in which water continuously passes through a coffee bed, carrying extracted compounds downward into the cup. Distinct from immersion in that fresh (low-concentration) water is always contacting the grounds, maintaining a concentration gradient that drives continued extraction. Includes all pour-over methods and drip machines.
Pulped natural — See: Honey process. Also called semi-washed in some markets.
Q Grader — A licensed professional coffee evaluator certified by the Coffee Quality Institute (CQI). Q Grader certification requires passing twenty-two tests across sensory, physical, and theoretical components. Q Graders evaluate green coffee using the SCA cupping protocol and assign scores on the 100-point scale. Considered the professional standard for green coffee evaluation in specialty markets.
Ratio — The proportional relationship between coffee dose and water weight in a brewing recipe. Expressed as coffee:water (e.g., 1:15 means 1g coffee per 15g water). The single most important recipe variable for controlling cup strength. See also: SCA Golden Cup Standard.
Robusta (Coffea canephora var. robusta) — One of the two primary commercial coffee species. Diploid, native to lowland sub-Saharan Africa. Contains approximately 2.2–2.7% caffeine. More disease-resistant and agronomically forgiving than Arabica. Produces dense crema in espresso. Flavor tends toward woody, earthy, and bitter in commercial production. Specialty Robusta, produced by quality-focused farms in Uganda, India, and Vietnam, has a higher quality ceiling than commercial production suggests.
S–Z
SCA Golden Cup Standard — The SCA’s recommended brewing parameters for filter coffee: coffee-to-water ratio of approximately 1:16.5 (55g per liter), water temperature of 90–96°C, and a dissolved solids target of 1.15–1.35% TDS in the brewed cup, corresponding to an extraction yield of 18–22%.
Second crack — A roasting event following first crack at approximately 224°C (435°F) in which CO₂ released by pyrolysis causes a second rapid expansion and cell wall fracture. Sounds like crackling, finer and more rapid than first crack. Roasting into or through second crack produces dark roast profiles with heavy roast flavor dominance, low acidity, and significant oil migration to the bean surface.
Single origin — Coffee sourced from one country of origin. Distinct from farm-level traceability (a single-origin coffee may be blended from multiple farms within one country) but more traceable than multi-origin blends.
Strength — The concentration of dissolved solids in brewed coffee, measured as total dissolved solids (TDS) as a percentage. Not synonymous with extraction yield — a coffee can be highly extracted (high yield) but dilute (low strength) if the ratio is weak, or weakly extracted but strong if the ratio is high. TDS is measured by refractometer.
Terroir — The combination of environmental factors — altitude, soil composition, climate, humidity, shade, rainfall distribution — that shape the flavor character of coffee grown in a specific place. Borrowed from wine and applied to coffee to describe the concept that geography influences flavor beyond genetics and processing. A genuine concept with real flavor implications, though difficult to isolate from variety and processing effects in practice.
Total dissolved solids (TDS) — The percentage of dissolved coffee solids in brewed coffee, measured by refractometer and expressed as a percentage. The SCA’s target for filter coffee is 1.15–1.35% TDS. Used alongside extraction yield on the SCA Brewing Control Chart to evaluate whether a brew is in the optimal zone.
Washed processing — A processing method in which the coffee cherry skin is removed by depulping, the mucilage is broken down by fermentation and/or mechanical washing, and the beans are dried in parchment. Produces clean, transparent cups that express origin and variety character directly. The default processing method in Kenya, Colombia, Rwanda, Ethiopia (for many producing areas), and most of Central America.
Wet process — See: Washed processing.
Yirgacheffe — A woreda (administrative district) in the Gedeo Zone of Ethiopia’s Southern Nations, Nationalities, and Peoples’ Region, and the most internationally recognized coffee origin in Ethiopia. Grown at 1,700–2,200 masl by smallholder farmers intercropping coffee with food crops under native shade. Famous for washed coffees with intense jasmine, bergamot, and citrus aromatics. Natural Yirgacheffes show tropical fruit and blueberry layered over the region’s signature floral quality.