Glossary

Coffee Glossary

Concise, evidence-based definitions for controlled liquid fermentation, brewing methods, analytical assays, and sensory vocabulary. Each entry links to the relevant Science Center article or brewing guide.

Fermentation: The biochemical process in which microorganisms (bacteria, yeast) convert the sugars and other substrates in a food into metabolites such as organic acids, alcohol, or gas. In coffee, it shapes the flavor precursors and the organic acid profile. → LAB Science
Controlled Liquid Fermentation: The processing of dried green coffee beans in a closed bioreactor with a proprietary lactic acid bacteria starter culture, under controlled temperature and time, for 24–48 hours. Distinct from spontaneous fermentation in that every parameter is measurable and repeatable. → Process Characterization
Lactic Acid Bacteria (LAB): A group of gram-positive bacteria that convert carbohydrates primarily into lactic acid. Includes genera such as Lactobacillus, Lactiplantibacillus, Pediococcus, and Leuconostoc. Holds GRAS (Generally Recognized As Safe) status in the U.S. and EU. → LAB Science
Bioreactor: A closed or semi-closed vessel designed for controlled microbial processes. Temperature, pH, oxygen, and agitation are continuously monitored. It provides the physical frame for controlled liquid fermentation. → Process Characterization
Mycotoxin: Toxic secondary metabolites produced by certain mold genera (Aspergillus, Penicillium, Fusarium) that can accumulate in food. The most common examples in coffee are ochratoxin A and aflatoxins; EU Regulation 2023/915 sets the legal limits. → Mycotoxins and Safety
Ochratoxin A (OTA): A nephrotoxic mycotoxin produced by Aspergillus and Penicillium species. The EU limit for roasted coffee is 5 µg/kg. Controlled LAB fermentation reduces risk through competitive exclusion. → Mycotoxins and Safety
Caffeine: The coffee bean's natural stimulant (1,3,7-trimethylxanthine). It is almost entirely stable through roasting; microbial demethylation can reduce it measurably (Arabica 5–10%, Robusta 8–10%). → What Happens to Caffeine?
Antioxidant: Molecules that can neutralize free radicals or act as electron donors. Antioxidant capacity in coffee is measured in vitro via DPPH and FRAP assays and correlates with phenolic content. → Antioxidants and Fermentation
Polyphenol: A class of plant-derived compounds that contain multiple phenol groups. The dominant polyphenols in coffee are the chlorogenic acid isomers, which account for a substantial share of antioxidant activity. → Antioxidants and Fermentation
Chlorogenic Acid (CGA): The dominant polyphenol in green coffee, comprising the caffeoylquinic acid isomers (3-CQA, 4-CQA, 5-CQA). It partially degrades during roasting; LAB fermentation modulates the isomer distribution. → Antioxidants and Fermentation
B Vitamins (B2, B3, B6): Riboflavin (B2), niacin (B3), and pyridoxine (B6). Certain LAB strains biosynthesize these vitamins. After controlled fermentation, coffee shows a measurable increase that is partially retained through roasting. → Chemical and Nutritional Effects
HPLC: High-Performance Liquid Chromatography. Used for the quantitative determination of compounds such as caffeine, chlorogenic acid, and trigonelline. The UV-detector variant is the standard method in coffee analysis. → Chemical and Nutritional Effects
DPPH Assay: An antioxidant-capacity assay that measures the neutralization of the 2,2-diphenyl-1-picrylhydrazyl radical. Results are expressed in Trolox Equivalents (TE). → Antioxidants and Fermentation
FRAP Assay: Ferric Reducing Antioxidant Power assay. Measures a sample's capacity to reduce Fe³⁺ to Fe²⁺ — reflecting the electron-donating dimension of antioxidant activity. → Antioxidants and Fermentation
TPC (Total Phenolic Content): Total phenolic-compound content measured with the Folin-Ciocalteu reagent. Results are expressed in Gallic Acid Equivalents (GAE). → Antioxidants and Fermentation
SCA Cupping: The Specialty Coffee Association's standard sensory evaluation protocol. Criteria such as aroma, acidity, body, balance, and sweetness are scored on a 100-point scale; 80+ qualifies as specialty grade. → Sensory Quality and Safety
Green Bean: The unroasted coffee seed, post-harvest processed and dried. Controlled liquid fermentation is applied at exactly this stage, before roasting. → Process Characterization
Arabica: The Coffea arabica species. Known for lower caffeine, a more complex aromatic profile, and balanced acidity. It accounts for the majority of the specialty coffee market.
Robusta: The Coffea canephora species. Higher caffeine, fuller body, more earthy profile. Often used in espresso blends to boost crema density.
Single Origin: Coffee that comes from a single region, farm, or processing facility. Because it is from a single source, it expresses terroir character in a pure form and adds traceability and transparency. → Single-origin collection
Blend: A composition built by combining coffees from two or more origins in defined proportions. Used in espresso and filter blends to achieve a stable flavor profile. → Products collection
Terroir: The combined imprint of a coffee's growing geography — altitude, soil, climate, microflora — on its sensory profile. The same variety can show a distinctly different flavor profile across terroirs.
Roasting: The process in which the green bean is treated at high temperature (180–230 °C) over a controlled time, generating its aromatic compounds. The Maillard reaction and caramelization are the main chemical drivers.
Grinding: Reducing the roasted bean to a particle size suited to the brewing method. Extra-fine for Turkish coffee and espresso; medium for V60; coarse for French press. → Brewing guide
Brewing: The act of bringing hot or cold water into contact with ground coffee to extract its soluble aromatics. Method, temperature, time, ratio, and filter material together set the final flavor profile. → Brewing guide
Espresso: An intense, concentrated coffee extracted in 24–27 seconds under 9 bar of pressure. 7–7.5 g dose, 85–94 °C water, extra-fine grind. The crema is an emulsion of oil + protein + CO₂. → Brewing guide: Espresso
V60: Hario's conical-filter pour-over. 17–21 g dose, 92–95 °C water, ~3 min total brew, 30 s bloom. The paper filter retains oils, producing a clear, articulate cup. → Brewing guide: V60
Chemex: A pour-over method designed in 1941 by Peter Schlumbohm, using a thick paper filter. 50–60 g dose (6-cup), 92–94 °C water, ~4 min. Produces one of the cleanest, brightest cups. → Brewing guide: Chemex
AeroPress: A combined immersion + pressure method invented in 2005 by Alan Adler. 17 g dose, 88–94 °C water, hand-applied 0.35–0.75 bar, 2–3 min. Combines espresso's cleanness with the complexity of pour-over. → Brewing guide: AeroPress
French Press: An immersion method that steeps coffee in hot water for 3–4 minutes and separates the grounds with a metal filter. 7–8 g per cup, 95 °C water. Lets oils through, producing a fuller, heavier-bodied cup. → Brewing guide: French Press
Moka Pot: A stovetop steam-pressure brewer developed by Bialetti in 1933. 11 g dose, 1–2 bar steam, ~100 ml yield. Delivers an intensity close to espresso. → Brewing guide: Moka Pot
Turkish Coffee: A traditional method brewed in a cezve: extra-fine ground coffee combined with cold water and heated on low-medium flame, never brought to a rolling boil. 5–7 g per cup. Inscribed on UNESCO's Intangible Cultural Heritage list. → Turkish Coffee product
Cold Brew: An immersion brew at 3–5 °C for 8 / 12 / 24 hours. 52–60 g dose, ~600 ml yield. The low temperature suppresses acid and bitterness extraction, giving natural sweetness and a smooth body. → Brewing guide: Cold Brew
Aroma: The sum of a coffee's volatile compounds as perceived by smell. Evaluated on both the dry grounds and the brewed beverage, and scored separately in the SCA cupping protocol.
Acidity: The bright, lively sensation a coffee creates on the palate. Citric, malic, lactic, and chlorogenic acids are the main sources. Controlled liquid fermentation increases lactic-acid dominance and smooths perceived acidity. → Why Smoother?
Body: The weight and fullness a coffee creates on the palate. Tied to oil content, dissolved-solids ratio, and filter type. The typical hierarchy: French press > pour-over > V60 > AeroPress.
Crema: The golden-brown foam atop an espresso — an emulsion of oil + protein + CO₂. A signal of freshness, correct pressure, and appropriate grind.
Flavor Profile: The combined description of a coffee's acidity, sweetness, body, aftertaste, and aromatic notes. Each dimension is scored 0–10 on the SCA cupping form.
Cupping: The professional method for evaluating coffee. At standardized grind, dose, and temperature, the aroma, taste, body, and aftertaste are assessed with a spoon. The SCA protocol is the industry standard. → Sensory Quality and Safety
Decaf (Decaffeinated Coffee): Coffee from which 97% or more of the caffeine has been removed. Typically done with a chemical solvent (ethyl acetate, dichloromethane) or liquid CO₂. Controlled liquid fermentation is NOT decaffeination — it only reduces caffeine by 5–10%. → What Happens to Caffeine?