Glossary

Ethanal (CH₃CHO) — the primary flavour compound in Fino Sherry (300–500 mg/L), produced by flor yeast oxidising ethanol via alcohol dehydrogenase. Aroma: green apple, almond, paint thinner. Also present at low levels in wine from normal fermentation (detection threshold ~50–100 μg/L). At high concentrations a wine fault; in Fino an intentional characteristic.

Long-chain fructose polymers (fructans) present in Agave tequilana piñas at ~15–25% dry weight. Not directly fermentable by yeast. Must be hydrolysed to freeform fructose and glucose by cooking (65–100°C, 24–48 hours in hornos/autoclaves) via inulinase enzyme activation before fermentation. Source: Waleckx et al. (2011) Bioresource Technology.

The copper pot still design mandated by the Cognac AOC (BNIC). Consists of: onion-shaped copper pot (chaudière), column (chapiteau/tête de maure), swan neck (col de cygne), and condensing coil (serpentin). Produces the brouillis (first distillation, 28–32% ABV) and bonne chauffe (second distillation, 68–72% ABV).

The single-column continuous still used for Armagnac production. Unlike Cognac's double-distillation pot still, the alambic armagnacais receives wine continuously and produces spirit continuously at 52–72% ABV. Patented 1818. The lower distillation ABV preserves more flavour-active congeners than Cognac's process, producing Armagnac's heavier, more aromatic character.

The percentage of ethanol in a beverage by volume at 20°C. Defined in EU as the number of litres of pure ethanol contained in 100 litres of the beverage measured at 20°C. Approximate formula: ABV% ≈ (Original Gravity − Final Gravity) × 131.25 for beer. All EU alcoholic beverages must declare ABV on the label.

The bitter-precursor compounds in hops (Humulus lupulus) — primarily humulone, cohumulone, and adhumulone. During wort boiling, alpha-acids isomerise to iso-alpha-acids (isohumulones), which provide beer's measurable bitterness (IBU). Typical content: 4–20% alpha-acids in commercial hop varieties. Aroma hops have low alpha-acid; bittering hops have high.

The dominant terpene in juniper berry essential oil (~50–80% of total terpene content). Responsible for the characteristic piney, resinous, fresh note of gin. Present in gin at ~10–30 mg/L. Also found in pine, fir, and spruce. At the concentrations in gin, it produces a fresh pine character rather than the 'turpentine' character perceived at higher concentrations.

Red and purple polyphenolic pigments in grape skins responsible for the colour of red wine. Chemically: glycosides of cyanidin, delphinidin, petunidin, malvidin, and peonidin. In wine, anthocyanins polymerise with tannins during ageing — forming more stable pigmented tannin-anthocyanin complexes (pyranoanthocyanins). Colour evolution from purple-red (young) to garnet/brick (aged) reflects this chemistry. Source: Boulton (2001) AJEV.

French designation system (controlled designation of origin) administered by INAO for wine, spirits, and other agricultural products. The highest quality tier in French law. Specifies geographic origin, permitted grape varieties or raw materials, viticulture/production methods, and minimum quality standards. Equivalent to EU Protected Designation of Origin (PDO/AOP). First AOC: Châteauneuf-du-Pape (1936).

An interspecific hybrid grape variety (Folle Blanche × Noah/Vitis riparia hybrid) unique to Armagnac within French AOC law. Developed by François Baco in the late 19th century as a phylloxera-resistant alternative. Contributes prune, violet, and spice character to Armagnac. EU generally prohibits hybrid varieties in quality wine/spirit AOCs; Armagnac has a specific exemption.

An oak container used for ageing wine, spirits, and other alcoholic beverages. Key variables: oak species (Quercus petraea/sessilis — French; Q. alba — American; Q. robur — Portuguese/Spanish/English); size (smaller barrel = more wood-to-liquid ratio = faster extraction); new vs used (new barrel extracts more tannin and vanillin); char/toast level (affects penetration depth of flavour-active compounds).

A German and Austrian Prädikat wine level — wine from individually selected overripe or botrytis-affected berries. Very high natural sugar content (minimum 110° Oechsle in most German regions). Rich, complex, often botrytis-influenced. Very rare and expensive. Above Auslese; below Trockenbeerenauslese (TBA) in sweetness. Source: German Wine Law (Weingesetz).

A holistic farming philosophy based on the work of Rudolf Steiner (Spiritual Science — 1924 Agricultural Course). Treats the farm as a self-sustaining ecosystem. Uses specific herbal preparations (numbered 500–508) and lunar/cosmic calendar planting and harvesting schedules. Certified by Demeter International. Evidence for quality improvement vs organic is disputed scientifically, though some prominent estates (DRC, Leroy, Chapoutier) practice biodynamics.

Beer Judge Certification Program — an American organisation founded 1985 that publishes the most widely used beer style guidelines globally (BJCP 2021 Style Guidelines) and certifies beer judges for homebrew competitions. Current BJCP Style Guidelines describe approximately 100+ distinct beer styles across 34 style categories, plus a separate mead judging guidelines document. Website: bjcp.org.

The second distillation in Cognac production — the brouillis (first distillation at 28–32% ABV) is redistilled in the Charentais alembic to produce the bonne chauffe at 68–72% ABV. The 'head' and 'tail' fractions are removed; only the 'heart' (coeur) passes to oak ageing. This double-distillation and precise cutting is the foundation of Cognac's refinement.

A fungal pathogen (grey mould) that, under specific conditions of alternating moisture and sunshine, produces 'noble rot' (pourriture noble) on grape berries — concentrating sugars and developing unique aromatic compounds (sotolon — 'curry leaf/fenugreek', β-damascenone, furaneol) while dehydrating the berry. Used for Sauternes, Tokaji Aszú, German Beerenauslese/Trockenbeerenauslese, and selected Austrian Prädikat wines. Under wet conditions without sunshine, Botrytis causes destructive grey rot.

The intermediate product of Cognac's first distillation in the Charentais alembic — wine at approximately 27–32% ABV. The brouillis retains much of the wine's aromatic character but concentrated. All brouillis from a given batch is redistilled ('double bouilleur' method is used for some Cognac houses where brouillis is added to fresh wine before redistillation). The bonne chauffe is the product of the second distillation.

A traditional British ale fermentation system, historically used in Burton-upon-Trent — particularly by Bass. The fermenting beer is connected to a series of large oak casks (unions), and excess yeast/foam blows off through tubes into a collecting trough, from which beer is returned to the fermenters. Produces a distinctive yeast strain selection over time. Still used by Marston's Brewery (Burton) for Pedigree.

A fermentation technique where whole, uncrushed grapes are fermented in a CO₂-saturated atmosphere. Within the intact berry, intracellular fermentation occurs via grape cellular enzymes (not yeast) — converting ~2% ABV of sugar to ethanol before the berry eventually ruptures. Produces very low-tannin, fresh fruit, bright-coloured wines with characteristic pear-drop (ethyl acetate) and banana (isoamyl acetate) character. Classic in Beaujolais Nouveau production. Source: Flanzy et al. (1987) Journal of Wine Research.

French term for grape variety or varieties used in a wine. In French wine, cépage is typically not declared on the label for AOC wines (geographic origin takes precedence); in the New World, the cépage name is the primary label declaration. 'Monocépage' = single variety; 'assemblage' = blend.

A ground-level wine storage building or cellar in Bordeaux (and some other French regions). Distinguishes from a cave (underground cellar, common in Burgundy and Champagne). Médoc châteaux typically have above-ground chais for barrel ageing because the water table makes underground cellars impractical.

The addition of sugar to grape must before or during fermentation to increase the final alcohol content. Named after Jean-Antoine Chaptal, French chemist and Minister of the Interior who advocated the practice c. 1800. Permitted in many cooler wine regions (Burgundy, Bordeaux, Germany — under specific conditions) where grapes cannot always ripen fully. Prohibited in warm regions (southern France, most of Spain, Italy, California). Not the same as sweetening — the sugar is fermented, increasing ABV not residual sugar.

A sparkling wine production method where secondary fermentation (which creates the bubbles) occurs in pressurised stainless steel tanks rather than in individual bottles (méthode traditionnelle). Named after Eugène Charmat (1907 patent), though also called cuve close or bulk method. Produces faster, less expensive sparkling wine — typical for Prosecco (Glera grape, Veneto/Friuli DOC), Lambrusco, and most commercial sparkling wine. Less complex than méthode traditionnelle but fresher and more fruit-forward.

A walled vineyard, historically enclosed by stone walls. In Burgundy, clos were typically created by monasteries during the medieval period to protect their vineyards and define ownership. Famous examples: Clos de Vougeot (50 ha, Grand Cru, Côte de Nuits — the largest Grand Cru in Burgundy, created by Cistercian monks in the 12th century), Clos de la Roche, Clos de Tart. A legally defined term in Burgundy under AOC regulations.

A single-vintage Tawny Port — aged in wood for a minimum of 7 years before bottling, then bottled within 12 months of the labelled vintage date. The label must show both the harvest year and the bottling year. Colheita is distinct from Vintage Port (bottled after 2 years, aged in bottle) — Colheita's extended wood ageing gives it Tawny-like oxidative character despite its single-vintage designation. Regulated by IVDP.

A collective term for all chemical compounds in alcoholic spirits and wines other than ethanol and water — including higher alcohols (fusel oils), esters, aldehydes, organic acids, and terpenes. Congeners contribute to the flavour, aroma, and character of spirits and wine. High-congener spirits (Jamaican rum, Scottish malt whisky) are more aromatic and complex; low-congener spirits (vodka, white rum) are lighter and more neutral. Some congeners (methanol, acetaldehyde in excess) are also associated with hangover and toxicity.

See Koelschip.

French term meaning 'growth' — refers to a specific vineyard, estate, or geographic sub-zone that produces wine of a defined quality level. Grand Cru = great growth (highest quality tier in Burgundy and Alsace). Premier Cru = first growth (second tier in Burgundy; top tier in Bordeaux). Cru Classé = classified growth (Bordeaux 1855 and subsequent classifications). The meaning and hierarchy differs substantially between wine regions.

The removal of the yeast deposit (lees) from a Champagne bottle after riddling (remuage). The bottle neck is frozen in brine, the crown cap is removed, and the frozen plug of yeast sediment is ejected by the pressure of the CO₂. The bottle is then topped up with the dosage (liqueur d'expédition) and corked. In traditional riddling, this is manual; modern production uses gyropalettes for riddling and automated dégorgement lines.

Spanish geographic designation system administered by the MAPA (Ministry of Agriculture, Fisheries and Food) and regional governments. Key tiers: DO (Denominación de Origen — equivalent to EU PDO); DOCa/DOQ (Denominación de Origen Calificada/Qualificada — higher tier, currently only Rioja and Priorat); VP (Vinos de Pago — single-estate designation). Spain also uses DOP (the EU term PDO) and IGP (EU term PGI).

See Dégorgement.

A wine estate in France, particularly in Burgundy, where the producer grows their own grapes and makes their own wine. Distinguished from a négociant (merchant who buys grapes or wine from growers). The most prestigious Burgundy wines are domaine-bottled (mise en bouteille au domaine). The term 'Domaine' is also used in Alsace and other French regions.

The addition of liqueur d'expédition (a mixture of reserve wine and sucrose) to Champagne after dégorgement to fill the space left by yeast ejection and to adjust the sweetness level. Determines the final category: Extra Brut (0–6 g/L), Brut (max 12 g/L), Extra Dry (12–17 g/L), Sec (17–32 g/L), Demi-sec (32–50 g/L), Doux (50+ g/L). Zero Dosage / Non-Dosé = no liqueur added.

Used in two distinct contexts: (1) In Champagne and traditional method sparkling wines — a second fermentation in the bottle to generate CO₂ (the méthode champenoise); (2) In some rum and sake production — referring to simultaneous saccharification and fermentation or sequential fermentation steps. Context determines meaning.

The residue remaining in the pot still after distillation of Jamaican rum — a liquid rich in organic acids (butyric acid, caproic acid, caprylic acid), yeast autolysate, amino acids, and fermentation by-products. When added back to the fermentation vessel (typically 10–25% by volume), dunder lowers pH, increases organic acid concentration, and provides ester synthesis precursors — the mechanism for Jamaican rum's characteristic high ester content. Source: Fahrasmane & Ganou-Parfait (1998) JAM.

A class of hydrolysable tannins found primarily in oak wood (particularly Quercus petraea and Q. robur) — principally vescalagin and castalagin. Released from oak during barrel ageing into wine and spirits. Initially astringent; polymerise over time to produce softer, more complex tannin-derived compounds. Limousin oak (Quercus petraea) releases more ellagitannins than American white oak (Q. alba), contributing to the different ageing character between French and American oak barrels.

Agave angustifolia — the most widely cultivated agave variety used for mezcal production (~90%+ of all mezcal production). Shorter maturation time than wild agave varieties (7–10 years vs 15–25+ years for Tobalá, Tepeztate). Espadín mezcal is the most commercially accessible style, producing moderate smoke, herbaceous, and roasted agave character.

The deliberate heating of Madeira wine in stainless steel tanks (estufas) to 45–50°C for a minimum of 90 days under IVBAM regulations. Accelerates Maillard reactions, caramelisation, and oxidation — producing Madeira's characteristic dried fruit, toffee, and coffee flavours. The alternative premium method is canteiro (natural tropical ageing in oak barrels for decades). The estufagem process replicates the vinho da roda ('wine of the journey') effect from 17th–18th century Atlantic trade ships.

A major ester (CH₃COOC₂H₅) produced during fermentation from the reaction of acetic acid and ethanol by yeast acetyltransferases. Detection threshold in wine: 100–150 mg/L. At low concentrations (below threshold) contributes to complexity; at fault levels (above ~150 mg/L) produces a vinegar/nail varnish character that is a significant wine and spirit fault. The defining congener in Light aroma (qīng xiāng) baijiu.

An ester (hexanoic acid ethyl ester) responsible for green apple, anise, and candy fruit aromas. Detection threshold in sake: ~0.05 mg/L. One of the two primary ginjo-ka compounds in premium sake (alongside isoamyl acetate). Also a major aroma compound in Strong aroma (nóng xiāng) baijiu, produced from caproic acid synthesised by Clostridium kluyveri bacteria in the mud pit fermentation.

The highest age designation for Tequila — minimum 3 years ageing in oak barrels (maximum 600L). Introduced as a formal NOM-006-SCFI category in 2006. Very complex, heavily oak-influenced, sometimes whisky-like in character. Significantly more expensive than Añejo. The category reflects the premium end of the tequila market's evolution toward aged expressions.

The final portion of the distillation run (also called 'tails') — the last liquid to exit the still after the heart cut. Contains heavier fusel alcohols, organic acids, and compounds that would produce off-flavours in the spirit if included. The skilled distiller's cut point between heart and feints is a critical quality decision. In Scotch malt whisky distillation, feints are typically recycled with the wash in the next distillation run.

The biochemical process by which yeast (primarily Saccharomyces cerevisiae) converts fermentable sugars to ethanol and carbon dioxide in the absence of oxygen (anaerobic). Key reaction: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ (glucose → ethanol + carbon dioxide). ATP yield: 2 ATP molecules per glucose (compared to 36–38 ATP in aerobic respiration). Additional by-products include glycerol, succinic acid, and many flavour-active compounds.

The addition of a fining agent to wine or beer to remove suspended particles, proteins, phenolics, and colloids — producing a clear, stable beverage. Common fining agents: bentonite (removes proteins — the most widely used); egg white/albumin (removes large tannin polymers — traditional Bordeaux château practice); isinglass (removes yeast — traditional British brewing); casein (milk protein — removes some tannins and colour). All fining agents must be declared on EU wine labels if potentially allergenic.

The tendency of yeast cells to aggregate into clumps (flocs) and settle to the bottom or rise to the top of the fermentation vessel after fermentation completes. High-flocculation yeasts are used in British ales (clear quickly, leave clean flavour). Low-flocculation yeasts stay in suspension longer — relevant for Hefeweizen (kept in suspension for the characteristic yeast haze). Flocculation is determined by yeast cell surface lectin proteins interacting with mannose residues on adjacent cells.

A film of film-forming yeast strains (Saccharomyces cerevisiae var. beticus and related species) that grows on the surface of Fino and Manzanilla Sherry in partially filled barrels. Flor acts as a biological barrier protecting the wine from oxidation while metabolising ethanol, glycerol, and acetic acid — producing the characteristic acetaldehyde (green apple/almond) character. Grows at 15–15.5% ABV; killed above ~16–16.5% ABV. Source: Moreno-García et al. (2018) FEMS Microbiology Reviews.

The addition of grape spirit (or other neutral spirit) to a wine during or after fermentation, raising its ABV above ~15–22%. Fortification for Port is done mid-fermentation (at 6–9% ABV) to arrest fermentation and preserve residual sugar. For Sherry, fortification occurs after complete fermentation to a dry base wine. For Madeira, fortification occurs after fermentation.

Obscure French term; see 'Foudre'.

A large oak barrel, typically 500L–6,000L or more, used for fermentation and/or ageing of wine. Unlike the standard 225L Burgundy pièce or 300L Bordeaux barrique, a foudre has a much lower wood-to-wine ratio — producing slower, more subtle oak extraction. Alsace (Hunawihr, Ribeauvillé) uses very large foudres (2,000–4,000L) for Riesling and Pinot Gris ageing, producing wines with minimal new-oak character.

Higher molecular weight alcohols (more than 2 carbons) produced as by-products of yeast amino acid metabolism during fermentation (Ehrlich pathway). Principally: isoamyl alcohol (3-methyl-1-butanol) — dominant fusel alcohol, banana/solvent aroma at high concentration; 1-propanol (propyl alcohol); 2-methyl-1-propanol (isobutanol). High fusel alcohol concentrations (above ~200 mg/L total) give spirits a harsh, 'hot' burning sensation and contribute to hangovers. Source: Lambrechts & Pretorius (2000) SAJEV.

A legal protection granted to a product with a specific geographic origin that has qualities, reputation, or characteristics essentially attributable to that origin. Two EU categories: PDO (Protected Designation of Origin) — all steps of production in the defined area (Champagne, Cognac, Parma Ham); PGI (Protected Geographical Indication) — at least one step in the defined area (Scotch Whisky). The TRIPS Agreement (WTO 1994) established international GI protection framework.

A three-carbon sugar alcohol (propane-1,2,3-triol) produced as a by-product of yeast fermentation. Major contributor to wine body, texture, and viscosity — present at 4–15 g/L in dry wine. In Sherry, glycerol is metabolised by flor yeast, contributing to Fino's lean, dry palate. Glycerol is also produced in large quantities during botrytised wine production. Not fermented by S. cerevisiae, so it remains in the finished wine. Glycerol has a mildly sweet taste (approximately 0.6× as sweet as sucrose).

Italian GI pomace brandy produced from grape pomace (skins, seeds, and stems remaining after wine pressing), minimum 37.5% ABV, produced and bottled in Italy. EU Regulation 2019/787 specifies production requirements. Distinct from Marc (French equivalent). Premium grappa is often single-variety pomace from specific grape varieties (Moscato di Canelli, Brunello di Montalcino, Amarone). Young unaged grappa can be harsh; wood-aged expressions develop more complexity.

2-Methoxyphenol — the primary smoke compound in peated Scotch malt whisky (from peat smoke during malt kiln drying) and in mezcal (from underground pit roasting of agave piñas). Detection threshold in spirits: ~22 μg/L. Range in smoky mezcal: 50–300+ μg/L. Produced from lignin pyrolysis during wood combustion or peat burning. Also produced in small quantities during barrel ageing. The same compound that is a defect in wine when at fault levels appears as a desirable quality in peated whisky and traditional mezcal.

A genus of wild, non-Saccharomyces yeast (also known by its anamorph Kloeckera) that dominates the surface of freshly harvested grapes and in the early stages of spontaneous fermentation. Apiculate (lemon-shaped) morphology. Sensitive to alcohol — typically outcompeted by S. cerevisiae when alcohol rises above ~4–5% ABV. Produces significant amounts of acetic acid (volatile acidity) and ethyl acetate if uncontrolled. In natural/minimal-intervention winemaking, early Hanseniaspora activity contributes to complexity.

Visible turbidity in a beverage caused by colloidal particles — protein-polyphenol complexes (in beer and white wine), yeast (in Hefeweizen, Pét-nat), pectin (in cider), crystalline tartrate precipitates (in wine), or colloidal polysaccharide. Haze can be intentional (Hefeweizen, NEIPA, pét-nat) or a fault (protein haze in filtered commercial beer or wine). Chill haze forms when cold causes protein-tannin complexes to precipitate but resolves on warming. Permanent haze does not redissolve.

Parallel fermentation (並行複発酵) — the unique biochemical mechanism of sake production in which koji mould (Aspergillus oryzae) continuously saccharifies rice starch to glucose at the same time as yeast (Saccharomyces cerevisiae) ferments the glucose to ethanol. This simultaneous saccharification and fermentation (SSF) enables sake to reach 18–20% ABV naturally — the highest natural fermentation alcohol level of any major beverage — because the gradual glucose release prevents yeast osmotic stress.

A NTA-designated premium sake type — rice polished to at most 70% seimaibuai, with a small permitted addition of pure alcohol (maximum 10% of the rice weight in pure alcohol). The alcohol addition is not to sweeten or fortify but to lighten body and extract aromatic compounds. Honjozo tends to be lighter and more aromatic than Junmai from the same rice and koji base. One of the two base premium sake designations below Ginjo and Daiginjo.

Hops — the plant whose female flower cones provide bitterness (alpha-acids → iso-alpha-acids/isohumulones during boiling), aroma (terpenes and thiols in late/dry hop additions), and antimicrobial compounds to beer. Domesticated hops are diploid. The two primary cultivated hop groups: European varieties (Saaz, Hallertau, Fuggles, East Kent Goldings — earthy/herbal/floral) and American varieties (Cascade, Centennial, Citra, Simcoe, Mosaic — citrus/pine/tropical). First documented in German beer records from 8th century CE.

A measure of the perceived bitterness of beer from isohumulone compounds (iso-alpha-acids derived from hop alpha-acids during wort boiling). Measured photometrically in the lab or calculated from known alpha-acid additions. Human perception threshold: approximately 5–10 IBU. Range: 5 IBU (Berliner Weisse) → 120+ IBU (Imperial IPA). Note: high residual sugar can mask bitterness, so perceived bitterness ≠ IBU number.

An ester (3-methylbutyl acetate) — one of the most important flavour compounds in fermented beverages. In sake: banana/pear character, the primary ginjo-ka compound. Detection threshold in sake: ~0.3 mg/L. In Hefeweizen: banana character (produced by POF+ Weizen yeast strains). In beer generally: at low concentrations contributes fruit complexity; at high concentrations a yeast fault character. Produced by yeast acetyltransferase (ATF1 gene product).

The skilled agave harvester who cuts mature Blue Weber agave (for tequila) or other agave species (for mezcal) using a long-handled cutting tool called the coa. The jimador reads the plant's maturity — assessing leaf colour, density, and the absence of a quiote (flower stalk) which signals the plant has consumed its fructan reserves. A skilled jimador can harvest 100–200 plants per day. Jimador knowledge is passed through family apprenticeship; the tradition is documented as an important cultural heritage element by CRT.

A NTA-designated premium sake type produced from only rice, koji, water, and yeast — no added alcohol (the word junmai means 'pure rice'). Current NTA regulations do not specify a minimum seimaibuai for Junmai (this was changed from the earlier 70% minimum). Junmai tends toward richer body, more umami-driven palate, and fuller mouthfeel than equivalent Honjozo expressions. The highest Junmai tier is Junmai Daiginjo (seimaibuai ≤50%).

The common name for the mould Aspergillus oryzae (and related Aspergillus kawachii in some applications) grown on grain. Produces amylase enzymes (alpha-amylase and glucoamylase) that convert starch to fermentable glucose. Essential in sake production (~20–30% of total rice batch is koji rice). Also used in miso, soy sauce, mirin, and shochu. Distinct from Chinese qu (which is a complex mixed-culture containing many organisms). The Japanese word koji (麹) covers multiple grain fermentation mould applications.

A large, flat, shallow open vessel (the Dutch/Flemish word translates roughly as 'cool ship') used in Lambic production to cool freshly boiled wort and simultaneously expose it to ambient microflora for spontaneous inoculation. Located at the top of the brewery with open louvers to allow cold air circulation. Only used October–April in Belgium (when ambient temperatures are cool enough to allow proper inoculation without spoilage organisms dominating). A typical koelschip holds 10,000–100,000 litres.

A diverse group of bacteria that produce lactic acid as a primary fermentation by-product. In wine: Oenococcus oeni (the primary organism conducting malo-lactic fermentation — MLF), Lactobacillus, Pediococcus. In Lambic beer: Pediococcus damnosus (primary lactic acid producer in months 3–8 of fermentation). In mead: sometimes present in traditional wild fermentations. In cider: responsible for malo-lactic fermentation that reduces malic acid to lactic acid, softening the cider.

A traditional stone or concrete fermentation/treading vessel, typically shallow and wide, used primarily in the Douro Valley for Port production and in some traditional Spanish wine regions. Treading grapes by foot in lagares is one of the most effective methods of extracting colour and tannin from thick-skinned varieties (Touriga Nacional, Tinta Roriz) because foot pressure is gentle enough not to crush seeds but firm enough to macerate skins effectively.

The sediment of dead yeast cells, grape pulp fragments, tartrate crystals, and other solids that accumulate at the bottom of a fermentation or ageing vessel. 'Ageing on lees' (sur lie) — maintaining contact between wine and fine lees — is a technique that adds texture, complexity, and autolytic yeast character (brioche, toasted bread, mushroom) to wine. Mandatory in Muscadet Sèvre et Maine sur Lie (Loire Valley). Also important in Champagne production (minimum lees contact: 15 months for NV, 36 months for vintage).

Quercus petraea (sessile oak) from the forests of Limousin and Tronçais in central France — the mandatory oak species for Cognac and Armagnac ageing. Characterised by a looser grain (larger pores) than American white oak, allowing faster oxygen ingress and more ellagitannin/vanillin release. Produces vanilla, dried fruit, spice, and rancio character over time. Also used for some premium wine barrel ageing.

A monoterpene alcohol (3,7-dimethylocta-1,6-dien-3-ol) found as a free compound in certain grape varieties (Riesling, Muscat, Gewürztraminer, Torrontés) and in hop varieties (coriander seed, bergamot orange). In gin, linalool from coriander seed and juniper is a primary aromatic compound — contributing floral, lavender, citrus character. In Riesling, free linalool (~0.1 mg/L threshold) contributes to the floral-terpenic aromatic profile. Produced biosynthetically via the mevalonate pathway in plants.

The extraction of colour, tannin, and aromatic compounds from grape skins (and seeds, stems) into grape juice/wine during or after fermentation. The duration, temperature, and method of maceration determines the concentration of phenolics in red wine. Cold maceration (pre-fermentation at 10–12°C): extracts colour without tannin. Warm maceration during fermentation: extracts both. Extended maceration (post-fermentation): further tannin extraction.

A dicarboxylic acid (HOOC-CH₂-CH(OH)-COOH) — the primary acid in apples and the second most important acid in grapes (after tartaric acid). Imparts a sharp, 'green apple' flavour. In wine, can be converted to softer lactic acid by malo-lactic fermentation (MLF) via Oenococcus oeni. In cider, the primary acid, also convertible by MLF. Unlike tartaric acid, malic acid is fully metabolised by MLF bacteria — its complete removal is possible.

The conversion of malic acid to lactic acid + CO₂ by lactic acid bacteria (primarily Oenococcus oeni). Reduces total acidity, softens the wine's flavour profile, increases microbial stability (no residual malic acid for subsequent bacterial fermentation), and adds buttery character (from diacetyl production). Encouraged in most red wine and some white wines (Burgundy white, Champagne). Inhibited in crisp, high-acid whites (Muscadet, German Riesling, Sauvignon Blanc, Champagne — depending on house style). Source: Lonvaud-Funel (1995) FEMS Microbiology Reviews.

The process of mixing crushed malted grain with hot water (typically 62–70°C for beer; 60–80°C for whisky) to activate malt enzymes (alpha-amylase and beta-amylase) that convert starch into fermentable sugars (principally maltose). The resulting sugar-rich liquid is called wort (beer) or wash (whisky). Mash temperature determines the ratio of fermentable to non-fermentable sugars — higher temperature (68–70°C) favours more non-fermentable dextrins → fuller-bodied beer.

The production method for Champagne and other premium traditional method sparkling wines: primary fermentation → base wine blending (assemblage) → second fermentation in bottle (with addition of tirage liqueur — sugar + yeast) → lees ageing (minimum 15 months NV, 36 months vintage for Champagne) → riddling (remuage — manual or gyropalette) → dégorgement → dosage → corking. Only wines from the Champagne AOC may legally use the term 'méthode champenoise'; others must use 'méthode traditionnelle.'

Mexican DO distilled spirit from any native agave species in 9 designated states (NOM-070-SCFI-2016, IMPI). Any agave — most common Espadín (Agave angustifolia). Traditional production: underground pit roasting of agave piñas → mezcal's characteristic smoky character (guaiacol, 4-methylguaiacol from lignin pyrolysis). Three production tiers: Mezcal · Mezcal Artesanal · Mezcal Ancestral. Mezcal is the broad category of which tequila is a subcategory.

Estate-bottled — the wine is bottled at the property where the grapes were grown and the wine was made. A significant quality indicator in Bordeaux (mis en bouteille au château) and Burgundy (mis en bouteille au domaine / à la propriété). Ensures the chain of custody from vineyard to bottle is controlled by one producer. Contrasted with négociant bottling (vin mis en bouteille par le négociant X).

The foam and bubbles in a sparkling wine. Quality of mousse is determined by the size and persistence of bubbles — very fine, long-persisting bubbles ('perles') indicate lower CO₂ pressure (closer to 5 atmospheres for Champagne than 6–7 for Cava or Prosecco) and longer lees ageing (which produces compounds that stabilise bubble nucleation). Nucleation sites in the glass (scratches, fibre fragments) initiate persistent bubble streams.

The freshly pressed, unfermented juice from grapes (or other fruit) before or during fermentation. In winemaking, 'must' typically includes the grape juice, skins, seeds, and sometimes stems before they are separated (for white wine, must is clarified before fermentation; for red, skins remain during fermentation for colour/tannin extraction). In cider: pressed apple juice is also called must before fermentation. In mead: the diluted honey solution prepared for fermentation.

Unpasteurised sake — bottled without the standard two pasteurisation steps (one after pressing, one before bottling). Fresh, slightly effervescent, active enzymatic character. More delicate and shorter-lived than standard sake. Requires refrigeration; shelf life is shorter than pasteurised sake. Highly seasonal in Japan — spring namazake release is a notable annual event. Namazake must be kept below 5°C throughout the supply chain.

An informal, non-legally defined category of wine produced with minimal intervention: grapes from organic or biodynamic viticulture, hand-harvested, fermented with ambient/wild yeast only, no fining or filtration, minimal or no SO₂ addition, no commercial yeast, no added sugar/acid/water. The natural wine movement emerged from France in the 1980s–1990s (Pierre Overnoy, Marcel Lapierre, Jules Chauvet). No consensus definition or certification standard exists globally; multiple proposed definitions are contested within the natural wine community.

A wine merchant who purchases grapes, juice, or finished wine from growers and either makes wine themselves (négociant-éleveur) or bottles and sells wine produced by others. Distinct from a domaine (estate producer). In Burgundy, major négociants (Jadot, Drouhin, Faiveley, Bouchard) blend wine from multiple appellations and producers, providing broader availability but typically less vineyard-specific character than domaine bottlings.

A Champagne (or sparkling wine) blended from multiple vintages to achieve a consistent house style — typically using a proportion of reserve wines (wines from previous vintages kept specifically for blending). The requirement for Champagne NV: minimum 15 months lees ageing after secondary fermentation in bottle (minimum 12 months of this on lees). Each major Champagne house has a 'house style' maintained vintage to vintage through NV blending.

A scale of grape must density used in Germany, Austria, and Switzerland — measuring the dissolved solids (primarily sugars) in grape must as a measure of grape ripeness. Named after Christian Ferdinand Oechsle (1774–1852). 1° Oechsle = 1 g of dissolved solids per 1 litre of water above water's specific gravity of 1.000. Minimum Oechsle levels define Germany's Prädikat categories (Kabinett = 67–82°Oe; Spätlese = 76–90°Oe; Auslese = 83–100°Oe; Beerenauslese = 110–128°Oe; Trockenbeerenauslese = 150–154°Oe depending on region).

Chemical reactions involving oxygen that alter the flavour, colour, and structure of wine and spirits. Desired controlled oxidation: the micro-oxygenation of barrel-aged wine/spirits through porous oak staves, the oxidative ageing of Oloroso Sherry and Madeira. Undesired oxidation fault: premature oxidation (prémox) in white Burgundy from cork failure or poor bottling; browning of white wine; flat, Madeira-like oxidative notes in wine exposed to too much oxygen at the wrong time.

The dominant grape variety in Sherry production (~90% of all plantings in the Marco de Jerez). A neutral, low-acid variety that produces a base wine ideally suited for fortification and biological ageing under flor — contributing minimal intrinsic flavour that allows the flor and ageing processes to define the wine's character. Makes poor unfortified wine but excellent Sherry base. Distinct from the Australian Palomino (a different clone).

Partially carbonised plant material (Sphagnum moss, heathers, roots) formed over thousands of years in waterlogged, acidic conditions. Used as fuel for drying malted barley in traditional Scotch whisky production — the combustion products (phenols, primarily guaiacol and 4-methylguaiacol from peat's lignin component; cresols; xylenols) penetrate the malt and carry into the distillate. Peating level measured in PPM (parts per million phenols in malt). Heavily peated: Laphroaig, Ardbeg (40–55 ppm); lightly peated: Highland Park (15–20 ppm); unpeated: Glenmorangie, Cardhu.

Daktulosphaira vitifoliae — a root louse originally native to eastern North America that devastated European vineyards from approximately 1863 (France: first confirmed Gard, southern France) to 1880+. Approximately 40% of French vines were destroyed. Solution: grafting European Vitis vinifera vines onto phylloxera-resistant American rootstocks (V. riparia, V. rupestris, V. berlandieri). Phylloxera has never reached Chile or Australia's Barossa Valley (natural barriers), allowing own-rooted vines in those regions.

A large class of plant secondary metabolites containing multiple phenol groups. In wine, include: tannins (proanthocyanidins from skins/seeds — contributing structure, astringency, colour stabilisation); anthocyanins (red pigments from skins); flavonols (quercetin, myricetin — co-pigmentation); hydroxycinnamates (caffeic acid, ferulic acid — oxidation substrates); stilbenes (resveratrol — of interest for purported health effects). Polyphenol concentration is higher in red than white wine; grape variety, climate, and winemaking technique all affect levels.

The solid material remaining after grape pressing — comprising skins, seeds, stems, and pulp fragments. Used as: (1) fertiliser returned to vineyards; (2) raw material for pomace brandy production (Grappa in Italy, Marc in France, Orujo in Spain); (3) source of tartrate crystals (industrial use in food and pharmaceutical industries). High in polyphenols and seeds that would contribute excessive bitterness if over-extracted.

A batch distillation vessel — a heated pot (typically copper) with an attached swan-neck leading to a condenser. Pot still distillation produces spirit in discrete batches; each run produces a distillate that includes heads (light, high-volatile fractions), heart (the desired spirit), and tails (heavy, high-boiling fractions). Used for Cognac (double pot still), Scotch malt whisky (double or triple), Irish pot still whiskey, heavy Jamaican rum. Produces richer, more congener-heavy spirit than continuous column stills.

The measurement unit for peating intensity of malted barley in Scotch whisky production — measuring the concentration of phenolic compounds (primarily guaiacol and related compounds absorbed from peat smoke during kiln drying) in the malt. Lightly peated malts: 5–15 ppm; medium peated: 15–30 ppm; heavily peated: 35–55 ppm; very heavily peated: 55+ ppm (Octomore from Bruichladdich reaches 167–258 ppm). Note: PPM in malt ≠ PPM in finished whisky (dilution and ageing reduce phenol levels significantly).

The mixed-culture fermentation agent used in baijiu production — a dried brick, ball, or powder of fermented wheat or grain inoculated with ambient wild moulds (Aspergillus, Rhizopus, Mucor), yeasts (Saccharomyces, Pichia, Torulaspora), and bacteria (Lactobacillus, Bacillus, Clostridium). Unlike koji (pure A. oryzae culture), qu's diverse microbial community produces the full spectrum of flavour compounds in baijiu. The specific qu composition determines the baijiu's aroma type. Source: Du et al. (2015) Applied Microbiology and Biotechnology.

A wine estate in the Douro Valley, Portugal — typically a self-contained farm on the steep schist valley slopes with vineyards, winery, and sometimes visitor facilities. IVDP grades all Douro quintas and vineyards on an A–F scale based on vine age, altitude, aspect, soil quality, yield, and variety composition. Single-quinta Vintage Ports (Quinta do Vesuvio, Quinta do Crasto, Quinta do Noval Nacional) are among the most collectible wines globally.

A distinctive aromatic and flavour note associated with very old Cognac, Armagnac, and some Madeira and Oloroso Sherry — described as walnut, dried fruit, oxidised fat, farmyard, and cheese rind. Produced by long oxidative ageing through complex reactions including oxidation of fatty acid esters, wood-derived lactone transformations, and Maillard-type reactions. Considered a marker of significant age and quality in premium Cognac (Sarni et al. 1990 AJEV) and Armagnac.

The concentration of fermentable sugars remaining in a beverage after fermentation — typically expressed in g/L. In wine: 'Dry' = RS below ~4 g/L (perception threshold for sweetness is approximately 3–5 g/L depending on acidity); 'Off-dry' = 4–12 g/L; 'Medium' = 12–45 g/L; 'Sweet' = 45–130 g/L; 'Very Sweet' = 130+ g/L. In Germany, Spätlese can be dry or sweet depending on how much RS the winemaker retains. In mead, high sorbitol in perry meads contributes perceived sweetness beyond what RS measurement indicates.

The process of gradually tilting and rotating Champagne bottles from horizontal to neck-down position over several weeks (manual riddling in traditional wooden pupitres) or days (mechanical gyropalettes) to consolidate yeast lees in the bottle neck before dégorgement. Traditional manual remuage: 6–8 weeks; gyropalette: 3–7 days. Skilled remeurs (riddlers) can hand-riddle up to 40,000 bottles per day.

The primary grape variety of Germany's Mosel, Rheingau, and Alsace wine regions — one of the world's greatest white wine varieties. Characterized by very high natural acidity (tartaric acid dominated), pronounced terpene and thiol aromatic profile (linalool, geraniol, TDN after ageing), and ability to express terroir with unusual precision. The 'petrol' note characteristic of aged Riesling comes from 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) formed from carotenoid degradation. Riesling ripens late and is frost-sensitive — suited to slate/schist soils that retain heat.

The primary yeast species responsible for alcoholic fermentation in wine, beer (ale), cider, mead, sake (alongside koji), and most distilled spirits. A eukaryotic ascomycete fungus. Under anaerobic conditions, produces ethanol and CO₂ from fermentable sugars (primarily glucose and fructose). Also produces hundreds of flavour-active by-products (esters, higher alcohols, glycerol, succinic acid) depending on strain, temperature, and nutrient availability. Genome sequenced 1996 — the first eukaryote fully sequenced.

The lager yeast — an allodiploid hybrid of Saccharomyces cerevisiae and Saccharomyces eubayanus. Ferments optimally at 7–13°C (bottom-fermenting). S. eubayanus was discovered in Patagonian beech forests in 2011 (Libkind et al. PNAS 2011). The hybridisation event that produced all commercial lager strains (Weihenstephan 34/70, Saaz group, Frohberg group) is believed to have occurred in Bavaria before the 15th century CE. The cold fermentation capability derives from S. eubayanus's cryotolerance.

A metamorphic rock formed by the transformation of existing rock under high temperature and pressure — producing a foliated (layered) structure. Key wine regions on schist soils: Douro Valley/Port (schist producing very low fertility and excellent drainage, vine roots penetrate to 10–20m), Priorat (Catalan llicorella — black slate/schist), Mosel (Devonian blue slate/Hunsrückschiefer), some parts of Beaujolais. Schist retains and radiates heat, providing warmth to vines in cool or marginal climates.

精米歩合 — the rice polishing ratio in sake production. Expressed as the percentage of the original rice grain remaining after milling. Lower number = more polishing = more outer layers removed = more delicate/aromatic sake. Ginjo: ≤60%; Daiginjo: ≤50%. Some premium Daiginjo may be polished to 30–40% seimaibuai. The outer layers of rice contain proteins (→ amino acids/aminosando off-flavours), lipids (→ fermentation inhibitors), and iron (→ yeast inhibitor/browning).

Jerez-Xérès-Sherry DO fortified wine from the Marco de Jerez, Andalusia, Spain (Consejo Regulador). Made primarily from Palomino Fino grapes. Key distinction: Fino/Manzanilla = biological ageing under flor yeast at 15–15.5% ABV; Oloroso = oxidative ageing at 17–18% ABV. Seven styles from Fino (pale/dry/floral) to Pedro Ximénez (very sweet/black/raisin). Aged in solera systems. Flor yeast produces characteristic acetaldehyde (300–500 mg/L in Fino).

Site-Specific Natural Isotope Fractionation by Nuclear Magnetic Resonance — an analytical technique developed by Gérard Martin at the University of Nantes for authenticating the geographic origin and detecting adulteration of alcoholic beverages. Measures site-specific deuterium isotope ratios in ethanol — which differ depending on fermentation substrate (grape, grain, beet, cane), climate, and geographic origin. Used in the EU wine databank (JRC Ispra) for wine authenticity verification. Source: Martin et al. (1986) JAFC.

A fractional blending and ageing system used for Sherry, Brandy de Jerez, aged Marsala Vergine, some Port (aged Tawny, Colheita), and some rum (Ron Zacapa). Wine/spirit is drawn from the oldest level (solera) and replenished from progressively younger levels (criaderas/añadas). The result: every bottled expression is a blend of multiple vintages, including trace amounts of very old wine. No vintage year appears on the label. The 'age' stated for aged Tawny Port (10/20/30/40yr) is the average age of the blend, certified by IVDP.

A 6-carbon sugar alcohol (D-glucitol) present at 30–80 g/L in perry pear juice (far higher than in apple juice, <1 g/L). Not fermentable by Saccharomyces cerevisiae (which lacks sorbitol dehydrogenase at industrially significant levels). Passes through fermentation intact — contributing perceived sweetness to 'dry' perry beyond what measured residual sugar indicates. Biosynthesised in pears via the sorbitol-6-phosphate pathway. Also present in smaller quantities in apple cider but not at levels affecting perceived sweetness. Source: Whiting (1970) JSFA.

A scale of beer colour measured photometrically at 430nm absorbance. SRM 2–3 = very pale straw (American Lager); SRM 4–7 = golden (Helles, Pilsner); SRM 8–14 = amber (Märzen, English Bitter); SRM 15–22 = brown (Brown Ale, Porter); SRM 30–40 = dark brown to opaque (Stout); SRM 40+ = very dark (Imperial Stout). Colour reflects roasted malt content.

The primary antimicrobial and antioxidant additive in winemaking — added as potassium metabisulphite (K₂S₂O₅) at various stages. Protects wine from oxidation and microbial spoilage. Exists in three forms in wine: molecular SO₂ (the active antimicrobial form, very low concentration); bisulphite SO₂ (bound to acetaldehyde and other carbonyl compounds); and sulphite/bound SO₂. EU maximum total SO₂: 150 mg/L in red wine; 200 mg/L in white and rosé; 300 mg/L in sweet wine. Allergen — must be declared on labels when ≥10 mg/L total SO₂.

A class of polyphenolic compounds with the property of precipitating proteins from solution — producing the dry, puckering 'astringency' sensation in red wine and some ciders and beers. In red wine: grape tannins (proanthocyanidins/condensed tannins) from skins, seeds, and stems; oak tannins (ellagitannins) from barrel ageing. Tannins polymerise during ageing, forming larger, softer complexes that produce softer, more integrated tannin character in aged wines. Detection threshold in wine: ~50 mg/L catechin equivalents.

The dominant organic acid in grapes (Vitis vinifera) — present at 5–10 g/L in ripe grape must. Chemically stable under most winemaking conditions (unlike malic acid, which can be degraded by MLF). Contributes the fundamental acidity structure of wine. Tartaric acid precipitates as potassium hydrogen tartrate crystals ('wine diamonds' or 'wine crystals') at low temperatures — harmless and not a wine fault, but removed by cold stabilisation in commercial wines. Tartaric acid is relatively rare in nature outside the genus Vitis.

The compound responsible for the 'petrol' or 'kerosene' note characteristic of aged Riesling (typically after 5–10+ years). Formed by acid-catalysed degradation of carotenoids (β-carotene, lutein) in the grape, releasing TDN as a volatilised ring compound. Detection threshold in wine: ~2 μg/L. At 20–100+ μg/L produces strong petrol character. Formed more rapidly in high-UV conditions (vineyards with low leaf canopy coverage) and accelerated by heat during ageing. Source: Simpson (1978) AJEV.

The addition of liqueur de tirage (a solution of sugar, yeast, and adjuvants) to base wine before secondary fermentation in bottle. The sugar in the tirage provides the substrate for the secondary fermentation that produces the CO₂ in Champagne. Approximately 24 g/L sugar in the tirage produces approximately 6 atmospheres of pressure in the bottle. The yeast (typically an active freeze-dried culture) must be capable of surviving at high pressure and alcohol concentration.

A historic sweet wine from the Tokaj wine region (Tokaj-Hegyalja), northeastern Hungary — one of the world's oldest and most prestigious botrytised wines. Produced from individually sorted botrytis-affected berries (Aszú berries) typically from Furmint and Hárslevelű grapes, added in traditional 'puttonyos' baskets to base wine or must. The current Tokaji Aszú designation requires minimum 120 g/L residual sugar. Tokaj was designated the world's first classified wine region (1737, by the Habsburg Emperor Charles VI — predating Bordeaux's 1855 classification by over a century).

Beer brewed within a Trappist (Cistercian Order of the Strict Observance) monastery, under the direct supervision of monks, as certified by the International Trappist Association (ITA) — signified by the Authentic Trappist Product hexagonal logo. Requirements: brewed within the monastery; brewed by or under monk supervision; primary purpose non-commercial (profits to monastery upkeep and charity). As of May 2026: 14 certified Trappist breweries globally, including Chimay, Westmalle, Westvleteren, Orval (Belgium), and examples in Netherlands, Austria, Italy, UK, USA, Spain, and France.

Agreement on Trade-Related Aspects of Intellectual Property Rights — a multilateral WTO agreement signed 1994, in force January 1995. Establishes minimum standards for international GI (Geographical Indication) protection. Article 23 provides enhanced protection for wine and spirits GIs specifically — preventing use of GI names even with qualifiers like 'style' or 'type' (e.g. 'Champagne style' or 'Cognac-type' are prohibited for non-Champagne/Cognac products in TRIPS-compliant jurisdictions). 164 WTO member countries as of 2026.

The primary grape variety of Cognac (~95% of Cognac vineyard plantings) and Armagnac production. Also known as Trebbiano in Italy. A neutral, high-acid, low-sugar variety that produces wine ideally suited for distillation into brandy — its high natural acidity preserves freshness and prevents bacterial spoilage during the months between harvest and distillation.

4-Hydroxy-3-methoxybenzaldehyde — the primary vanilla-scented compound extracted from oak wood during barrel ageing. Released from lignin degradation (lignin → coniferaldehyde → vanillin) during the heat-driven modification of oak staves and during the ageing process as the spirit or wine diffuses into the wood. American white oak (Quercus alba) produces more vanillin than French oak (Q. petraea) due to its lower ellagitannin/higher extractable lignin ratio. XO Cognac typically contains 3–7× more vanillin than VS from the same house.

Fresh sugarcane juice (also spelled vesou or vesou) — the raw material for rhum agricole production, including Martinique AOC. Pressed from freshly harvested sugarcane within hours of cutting to prevent fermentation or oxidative deterioration. Contains approximately 15–17% fermentable sugars. The use of vesou rather than molasses is the defining characteristic of agricole rum, producing a lighter, grassy, fresh-flavoured spirit compared to molasses-based rum.

The year in which the grapes were harvested (for wine) or in which production began (for spirits with age statements). In wine: a 'declared vintage' in Port refers to exceptional years where a shipper officially declares that the wine of that year merits Vintage Port production. In Champagne, vintage Champagne must be at least 85% from the declared harvest year (with minimum 36 months lees ageing). In Armagnac, vintage expressions document a specific harvest year (less common than Cognac — most spirits are non-vintage blends).

The acetic acid content of wine — arising from acetic acid bacteria (Acetobacter, Gluconobacter) converting ethanol to acetic acid in the presence of oxygen. Legal maximum for EU wine: 1.20 g/L (acetic acid) for white/rosé wine; 1.50 g/L for red wine. VA above legal limits is a wine fault; below threshold, small quantities contribute complexity. In Flanders Red Ale and some natural wines, deliberate Acetobacter activity is accepted. Detection threshold in wine: approximately 0.6–0.9 g/L.

The fermented liquid produced before distillation in Scotch malt whisky and other grain whisky production — essentially an unhopped beer of approximately 7–9% ABV produced by fermenting malted barley wort with commercial yeast (or in the case of Bourbon, corn mash with sour mash addition). The wash is distilled in the pot still (wash still) first to produce the 'low wines' before redistillation in the spirit still.

South Africa's geographic designation system — administered by the Wine and Spirit Board under the Liquor Products Act 60 of 1989 (DAFF). Four hierarchical tiers: Geographical Unit → Region → District → Ward. Strict 100% geographic rule — all grapes must come from the stated origin (stricter than Australia, USA, or New Zealand's 85% rules). Vintage requires 85% from stated year. Varietal requires 85% of stated variety.

The sweet, sugar-rich liquid produced from mashing malted grain with hot water. Wort contains maltose, dextrins, proteins, minerals, and other compounds from the malt that will be fermented by yeast to produce beer. Wort is clarified (in a lauter tun or whirlpool) after mashing, then boiled with hops for 60–90 minutes, which isomerises alpha-acids to iso-alpha-acids (bitterness), sterilises the wort, and evaporates undesirable volatile compounds.

A Cognac age designation requiring a minimum of 10 years oak ageing (raised from 6 years in 2018 by BNIC). In the Cognac classification hierarchy: VS (2yr) < VSOP (4yr) < XO (10yr) < XXO (14yr). Some major houses (Rémy Martin, Hennessy) also use 'Hors d'Âge' for their oldest blends above XO. In Armagnac, the equivalent designation is 'XO' (also subject to minimum ageing requirements under BNIA regulations).

The component of nitrogen in grape must or honey-water solution that can be utilised by yeast — comprising free amino nitrogen (FAN) and ammonium salts (NH₄⁺). YAN is essential for yeast health, replication, and flavour-positive fermentation. Honey is particularly YAN-deficient (often <20 mg/L YAN vs 200–400 mg/L in grape must) — causing nitrogen-stressed mead fermentations that produce excess fusel alcohols. Solution: supplementation with diammonium phosphate (DAP) and organic YAN sources (Fermaid-O). Source: Schramm (2003) Compleat Meadmaker.

Unicellular fungi — primarily Saccharomyces cerevisiae (wine, ale beer, spirits) and Saccharomyces pastorianus (lager) — that drive alcoholic fermentation, converting sugars to ethanol and CO₂. Single S. cerevisiae cell: approximately 5–10 μm diameter. Typical fermentation: inoculate at ~1 million cells/mL, cell count rises to 100–200 million cells/mL at fermentation peak, then declines as alcohol rises and nutrients deplete. Non-Saccharomyces yeasts (Hanseniaspora, Torulaspora, Lachancea, Metschnikowia) contribute complexity in spontaneous fermentations.

The chemistry and science of fermentation — particularly applied to the brewing and winemaking industries. From Greek zymo- (leaven/yeast) + -ourgia (working). The study of yeast metabolism, sugar conversion, ester formation, flavour compound production, and fermentation management. Zymurgy is the name of the official journal of the American Homebrewers Association. Louis Pasteur's foundational work on fermentation (1857–1864) established modern zymurgy as a scientific discipline.