Coffee Glossary: The Complete Specialty Coffee Encyclopedia

A naturally occurring purine alkaloid produced by the coffee plant as an evolutionary defense against insects.

The bright, sparkling, lively sensory sensation in coffee produced by organic fruit acids (citric, malic, phosphoric).

A chemical compound formed naturally in foods during high-temperature cooking and roasting through the Maillard reaction.

A portable manual piston brewer using mild pneumatic air pressure to press slurry through a paper or metal filter.

A classic Italian dessert beverage featuring a scoop of artisanal vanilla gelato "drowned" with a fresh hot shot of espresso.

The sensory flavors, sweetness, and tactile sensations lingering in the throat and palate after swallowing coffee.

Disturbing or stirring coffee grounds during brewing to accelerate extraction and promote even water contact.

Espresso diluted with hot water to yield a cup resembling drip coffee strength while preserving rich espresso aromatics.

Fermenting whole coffee cherries or pulped seeds inside sealed, oxygen-free tanks with one-way valves.

Coffea arabica — the premium global coffee species comprising 60–70% of world production, grown at high elevations.

The airborne volatile fragrances released from freshly ground coffee (dry fragrance) and brewed coffee (wet aroma).

Vigorously slurping coffee from a cupping spoon to aerosolize liquid across the palate and olfactory receptors.

A drying, puckering sensation on the tongue caused by tannins and polyphenols binding to salivary proteins (characteristic of over-extraction).

The harmonious equilibrium where sweetness, acidity, body, and bitterness complement one another without one dominating.

Dissolved alkalinity ($HCO_3^-$) in brewing water that neutralizes natural fruit acids, regulating perceived cup sharpness.

A historic layered beverage from Turin, Italy, crafted with rich liquid drinking chocolate, espresso, and cold heavy cream.

A harmonious combination of coffee beans from different origins, processing methods, or varieties.

A solid, hole-less metal portafilter basket used for backflushing espresso machine group heads with cleaning detergent.

The initial pour of hot water over fresh coffee grounds, causing rapid release of trapped CO₂ gas and swelling of the coffee bed.

The tactile weight, thickness, and viscosity of coffee liquid in the mouth, ranging from light/tea-like to heavy/syrupy.

A portafilter with its bottom spouts machined away, exposing the underside of the filter basket.

A legendary heirloom Arabica variety originating on the island of Réunion (formerly Bourbon), prized for sweetness and complex acidity.

An American espresso drink prepared with steamed half-and-half dairy cream rather than standard whole milk.

The quantitative relationship between dry coffee grounds and brew water, expressed as a ratio (e.g., 1:16 means 1g coffee per 16g water).

The total contact duration between brew water and coffee grounds from initial saturation until filtration finishes.

A tasting descriptor referring to crisp, lively, upfront acidity that illuminates other subtle flavor notes.

A coffee grinder using two interlocking abrasive burrs (flat or conical) to crush beans into precise, uniform particles.

Water that flows around the coffee bed without dissolving grounds, or hot water added directly to concentrate after extraction.

The global benchmark commodity exchange for commercial Arabica coffee futures contracts traded in New York.

Strong brewed drip or French press coffee combined with equal parts steamed milk (traditionally French breakfast style).

Natural diterpene lipids present in coffee bean oils that pass freely into unfiltered coffee (French press, espresso, Turkish).

A traditional espresso beverage featuring equal parts espresso, steamed milk, and dense microfoam (traditionally 5–6 oz).

Gas generated during pyrolysis and roasting that remains trapped in cell structures, causing the bloom during brewing.

An anaerobic processing adaptation from winemaking where whole cherries ferment in sealed tanks flushed with carbon dioxide ($CO_2$).

The dried outer fruit pulp and skin of the coffee cherry, brewed as a fruity, tea-like infusion.

A natural dwarf mutation of Bourbon discovered in Brazil, offering high yields and crisp citric acidity.

A brewing flaw where water carves paths of least resistance through an uneven coffee bed, causing localized over-extraction alongside under-extracted dry pockets.

An iconic hourglass glass pour-over brewer developed in 1941 by Dr. Peter Schlumbohm.

The complete fruit of the coffee tree containing skin, pulp, mucilage, parchment, and two paired seeds (beans).

A dominant family of polyphenol antioxidant esters found in green coffee that degrade during roasting into caffeic and quinic acids.

A medium-light roast dropped just after the completion of first crack, balancing origin acidity with early caramelization.

A hybrid brewer combining full immersion steeping with a draw-down valve that releases coffee when placed on a cup.

An immersion extraction method where coarse coffee grounds steep in room-temperature or chilled water for 12 to 24 hours.

A multi-layered cup that shifts and reveals different flavor notes as the beverage cools through different temperature zones.

Espresso "cut" with an equal volume of warm steamed milk with little to no foam (1:1 ratio, typically 4 oz total).

An aromatic emulsion of microscopic carbon dioxide bubbles suspended in liquid espresso, stabilized by coffee lipids and proteins.

The standardized professional method for evaluating coffee lots by steeping coarsely ground coffee in bowls without a filter.

A specialized, deep, round, silver- or gold-plated spoon designed to hold 4–5ml of coffee for aspirating.

Coffee roasted to or beyond second crack with visible surface oils, characterized by smoky, chocolate, and roasty notes.

Coffee beans that have undergone specialized solvent or water processing to remove 97% to 99.9% of natural caffeine.

The natural escape of carbon dioxide gas trapped inside roasted coffee bean cells during pyrolysis.

The physical compact mass per volume of a green coffee bean, strongly correlated with high cultivation elevation.

The systematic calibration of grind size, dry dose, liquid yield, and shot duration to achieve optimum sensory balance.

A transparent sourcing model where coffee roasters purchase directly from producers, bypassing middle brokers.

Italian for "double" — a double espresso shot pulled using 16–20g dry coffee dose, yielding 32–40g liquid.

The exact mass of dry ground coffee weighed in grams prior to brewing.

A small metal or plastic container used to weigh whole beans and catch ground coffee from a grinder before transfer.

The final phase of pour-over percolation where water recedes completely through the coffee bed into the decanter.

Coffee brewed by hot water dripping through coffee grounds contained within a paper, cloth, or metal filter.

The height above sea level where coffee is cultivated, typically between 1,000 and 2,200 meters in specialty regions.

A concentrated 25–35ml beverage extracted by forcing hot water (90–96°C) at 9 bars of pressure through compacted fine grounds.

The dissolution of soluble organic compounds, acids, lipids, and carbohydrates from roasted grounds into water.

The percentage of dry coffee mass dissolved into the brewed liquid, calculated as (Liquid Yield × TDS%) / Dry Dose.

An ethical certification system establishing guaranteed minimum floor prices and community development premiums for farmers.

The actual price paid directly to the coffee producer before export, shipping, milling, and broker markups are applied.

The perforated metal cup seated inside a portafilter that holds the tamped puck of ground coffee.

Microscopic coffee dust particles (<100 microns) produced during grinding that extract almost instantaneously.

An audible popping sound around 196°C (385°F) during roasting caused by steam pressure rupturing bean cell walls.

An Australasian specialty drink combining a double espresso or double ristretto with smooth, liquid microfoam (5–6 oz).

A circular visual diagram of sensory descriptors organized into concentric rings from broad categories to specific notes.

The speed at which water passes through the coffee bed or is poured from a kettle, measured in grams per second (g/s).

An evolving coffee movement prioritizing agricultural equity, climate sustainability, scientific water chemistry, and hyper-traceability.

A Greek iced beverage shaken with instant spray-dried coffee, water, sugar, and evaporated milk until frothy.

A classic immersion brewer where coarse coffee grounds steep in hot water for 4 minutes before a metal mesh plunger separates the grounds.

A brew method where all ground coffee remains fully submerged in water for the entire extraction duration.

The concentration of calcium ($Ca^{2+}$) and magnesium ($Mg^{2+}$) mineral ions in water that bind to and extract coffee flavor compounds.

A rare Ethiopian wild heirloom variety famously cultivated in Boquete, Panama, celebrated for jasmine, bergamot, and peach complexity.

A cortado served specifically in a 4.5 oz Libbey Gibraltar fluted glass, popularized by Blue Bottle Coffee in San Francisco.

A kettle featuring a tapered, curved spout designed for millimeter-precise flow control during pour-over brewing.

Raw, unroasted, dried coffee seeds stripped of cherry pulp and parchment, ready for shipment and roasting.

The physical particle size distribution of crushed coffee beans, ranging from ultrafine (Turkish) to extra-coarse (Cold Brew).

The brass brewing assembly on an espresso machine into which the portafilter locks to receive pressurized hot water.

A 60-degree cone pour-over dripper with spiral interior ribs and a large single exit hole.

The empty clearance between the tamped coffee puck surface and the espresso machine shower screen.

A processing method where cherry skin and pulp are removed, but sticky sugar mucilage is left clinging to the bean during sun drying.

Extracting soluble coffee components by steeping grounds in hot water rather than allowing water to pass through under gravity.

Brewing with the AeroPress assembled upside down so coffee and water steep without early leakage before pressing.

A warm cocktail made with hot black coffee, Irish whiskey, and brown sugar, topped with gently floated chilled heavy cream.

A flat-bottom pour-over dripper using rippled wave filters and three small exit holes for even extraction.

A reinforced container with a rubber-coated strike bar used to knock spent coffee pucks out of portafilters.

An espresso drink with steamed milk and a thin layer of microfoam, typically served in an 8 to 12 oz cup.

Coffea liberica — a distinct, large-seeded coffee species grown primarily in the Philippines and Malaysia with woody, floral notes.

Coffee beans roasted to the end of first crack, maximizing origin terroir, delicate fruit acidity, and floral aromatics.

Natural coffee bean fats and waxes accounting for 10–15% of Arabica dry weight, contributing to silky mouthfeel.

A double espresso pulled directly on top of 4–6 oz of hot water, preserving the undisturbed crema and aroma.

An espresso shot pulled with an extended brew ratio (1:3 to 1:4), running more water through the same puck.

Italian for "stained" — an espresso shot lightly marked with a small dollop of foamed milk.

A non-enzymatic browning reaction between amino acids and reducing sugars during roasting, generating hundreds of aromatic melanoidins.

A balanced roast level falling between first and second crack, presenting sweet milk chocolate, caramel, and balanced acidity.

Complex brown polymers formed during roasting that provide color, body, crema stability, and rich caramelized flavors.

A limited, traceable lot of coffee harvested from a specific parcel or high-elevation plot on a single farm.

An espresso beverage combining rich espresso, steamed milk, and cocoa or chocolate sauce.

A stovetop brewer utilizing steam pressure generated in a lower boiler to force boiling water up through coffee grounds.

The physical texture and tactile perception of brewed coffee (e.g. silky, buttery, creamy, chalky, juicy).

Drying intact whole coffee cherries in the sun on raised beds for weeks before mechanically hulling the dried fruit.

Cold brew coffee infused with pressurized nitrogen gas and dispensed through a stout tap faucet.

Extracting too high a percentage (>22%) of coffee bean mass, resulting in harsh bitterness, astringency, and dryness.

A natural genetic mutation occurring in ~5% of cherries where only one rounded bean develops instead of two flat-sided seeds.

A brewing dynamic where hot water flows continuously through a porous bed of grounds under gravity or mechanical pressure.

A single shot of espresso topped with silky microfoam in a 3 to 4 oz demitasse or duralex glass.

A digital electronic feedback mechanism (Proportional-Integral-Derivative) maintaining boiler temperature precision to ±0.5°C.

The handled metal tool that holds the coffee basket and locks securely into an espresso group head.

A manual percolation brewing technique using a conical or flat-bottom dripper with hot water poured in steady spirals.

Saturating the espresso puck with low-pressure water (1–3 bars) for several seconds before ramping to full 9-bar extraction.

The compacted, disc-shaped bed of coffee grounds inside an espresso portafilter basket.

The sequence of distribution, de-clumping, leveling, and tamping performed to optimize puck uniformity before pulling espresso.

A thin mesh stainless steel disc placed on top of a tamped espresso puck before brewing.

Dividing pour-over water into several distinct smaller pours with brief pauses to control thermal stability and bed height.

Thermal decomposition of organic compounds at high roasting temperatures (>200°C) without oxygen, generating volatile aromatic oils.

A certified professional coffee cupper trained and certified by the Coffee Quality Institute (CQI) to score specialty coffees.

Adding a single droplet of water or a quick mist to whole coffee beans before grinding to eliminate static electricity.

A standard cup of brewed drip coffee with a single shot of espresso added for elevated strength.

An optical laboratory device measuring how light bends through a coffee droplet to calculate exact Total Dissolved Solids (TDS%).

Multi-year direct purchasing agreements between roasters and producers ensuring price stability and iterative quality investments.

The perception of flavor aromas passing from the back of the mouth up into the nasal cavity while swallowing.

A restricted espresso shot pulled at a tight 1:1 to 1:1.5 ratio (e.g. 18g dose yielding 18–27g liquid), accentuating viscosity.

The calendar day coffee beans were roasted; specialty beans are best enjoyed 7 to 30 days post-roast date.

Coffea canephora — a hardy coffee species containing almost double the caffeine of Arabica, high crema potential, and woody bitterness.

The global non-profit trade association that establishes industry-wide coffee standards, education, and competitive rules.

A standard sorting metric measuring green coffee bean size through circular perforated metal sieves (e.g. Screen 18).

A secondary, sharper snapping sound at ~224°C (435°F) caused by $CO_2$ breaking down the woody cellulose structure of the bean.

Coffee harvested exclusively from one specific country, growing cooperative, washing station, or single estate.

A theatrical two-chamber glass brewer using vapor pressure and vacuum suction to immerse and filter coffee.

The mixture of hot water and ground coffee brewing together in an immersion or percolation vessel.

Arabica coffee scoring 80 points or higher on the standardized 100-point SCA cupping evaluation scale.

A stainless steel pipe connected to a boiler that ejects dry pressurized steam to froth and texture milk.

A pathway in the Maillard reaction where amino acids convert into volatile aldehydes and ketones, producing roasted nutty and bready aromas.

The natural perception of ripe sweetness derived from fully developed sucrose and caramelized carbohydrates.

Compressing loose coffee grounds inside the portafilter using a flat metal tamper to form an airtight, uniform puck.

Comparative sensory descriptors on a coffee bag (e.g., "jasmine, peach, honey") describing natural aromatic associations.

The concentration of dissolved coffee compounds in brewed coffee, expressed as a percentage and measured by refractometer.

The total environmental context of coffee growth: soil composition, rainfall, altitude, temperature swings, and sunlight.

The early 2000s culinary movement celebrating coffee as an artisanal agricultural product with origin transparency and light roasting.

A published audit by specialty coffee roasters disclosing FOB prices, farmgate prices, lot volumes, and grower identities.

A bitter alkaloid in green coffee that thermally breaks down during roasting to synthesize vitamin B3 (niacin) and pyridines.

Ultrafine coffee grounds simmered with cold water and optional sugar in a copper pot (cezve / ibrik) and served unfiltered.

One of the foundational genetic lineages of Coffea arabica, known for clean sweetness and elegant floral cup quality.

Failing to dissolve sufficient soluble mass (<18%), leaving the brew sour, salty, thin, and hollow.

Processing method where skin and fruit pulp are mechanically stripped, and mucilage is fermented and washed clean with water before drying.

A measurement of unbound water in green coffee beans; specialty green coffee must measure between 0.53 and 0.60 $a_w$ for storage stability.

Total dissolved mineral content in brewing water; the SCA recommends 50–175 ppm total hardness for balanced extraction.

The scientific dictionary of 110 standardized flavor, aroma, and texture attributes published by World Coffee Research.

Stirring coffee grounds with thin acupuncture needles (0.25–0.4mm) to break clumps and homogenize particle distribution.

A traditional Indonesian processing method where parchment is removed while beans are still moist (30–35% moisture).

The final mass of liquid coffee collected in the cup, weighed accurately in grams.