Whisky glossary

The mandatory US name-and-address statement, whose introductory phrase discloses which operation the named company actually performed: 'distilled by' for the distiller, 'bottled by' for the bottler, and 'blended by' or 'produced by' for a processor.

A declaration of the time the spirit spent in cask, which must refer to the youngest component in the bottling. For Scotch it must be expressed in years; in the US, age means time stored in oak after distillation and before bottling.

Whisky from a fermented mash of 100% malted barley, produced and distilled at a single US distillery at 160° proof or less, stored only in the United States in used, charred new or uncharred new oak barrels of 700 litres maximum. 'Straight' adds a two-year minimum.

A blend of two or more Single Malt Scotch Whiskies distilled at more than one distillery, with no grain whisky component.

A blend of one or more Single Malt Scotch Whiskies with one or more Single Grain Scotch Whiskies.

In the United States, a mixture containing at least 20% straight whisky on a proof-gallon basis, combined with whisky and/or neutral spirits — meaning up to 80% may be neutral spirit.

A US labelling term for spirits of one class and type, distilled by one distiller at one distillery in a single distilling season, stored at least four years in wood, reduced only with pure water, and bottled at exactly 50% ABV. The label must show the distillery's name and the DSP numbers of the distilling and bottling plants.

Whisky made in the United States from a fermented mash of not less than 51% corn, distilled at not more than 160° proof (80% ABV), entered into charred new oak barrels at not more than 125° proof, and bottled at not less than 80° proof. No colouring, flavouring or blending materials of any kind may be added.

Whisky bottled at or very near the strength at which it came out of the cask, without reduction to a standard bottling strength.

Spirit distilled on the island of Ireland from a mash of malted cereals, with or without other whole grains, saccharified by the diastase of the malt, distilled below 94.8% ABV, and matured at least three years on the island of Ireland in wooden casks not exceeding 700 litres; minimum 40% ABV.

Under the JSLMA labelling standards: whisky whose raw materials are limited to malted grains, other cereals and water extracted in Japan, saccharified, fermented and distilled at a distillery in Japan below 95% ABV, matured in Japan at least three years in wooden casks of no more than 700 litres, and bottled in Japan at 40% ABV or more.

A US class of whisky distilled at more than 160° proof and stored in used or uncharred new oak barrels. It is a whisky in its own right, not a mixture with neutral spirit.

In the United States, whisky from a fermented mash of not less than 51% rye, distilled at 160° proof or less and stored in charred new oak at 125° proof or less. 'Straight rye' adds a two-year minimum and bars additives.

Whisky produced in Scotland from water and malted barley (whole grains of other cereals may be added), converted only by endogenous enzymes and fermented only by yeast at a single distillery, distilled below 94.8% ABV, matured at least three years in Scotland in oak casks not exceeding 700 litres, and bottled at no less than 40% ABV with nothing added but water and plain caramel colouring.

Scotch whisky distilled at a single distillery that is neither Single Malt Scotch Whisky nor a Blended Scotch Whisky. It is defined by exclusion, not by grain content.

Scotch whisky distilled in one or more batches at a single distillery, from water and malted barley without the addition of any other cereals, in pot stills.

Irish whiskey distilled in pot stills from a mash containing a minimum of 30% malted barley and a minimum of 30% unmalted barley, with up to 5% of other cereals such as oats or rye. 'Single' requires that all of it was distilled at one distillery.

Bourbon stored in charred new oak barrels at 125° proof or less for a minimum of two years, with no neutral spirits and no colouring, flavouring or blending materials.

Whiskey manufactured in Tennessee from a mash of at least 51% corn, distilled to no more than 160° proof, filtered through maple charcoal before ageing, barrelled at no more than 125° proof in new charred oak in Tennessee, and bottled at not less than 80° proof.

The acidic, de-alcoholised liquid recovered from the base of the beer still — also called stillage or setback — recycled into cooking and fermentation to acidify the mash.

The two-column continuous still patented by Aeneas Coffey in 1830, ancestor of the modern grain-whisky still; the term now most often refers to the surviving Coffey stills Nikka uses in Japan.

A continuous still in which wash is fed partway up a vertical column and rises against descending liquid over plates, achieving repeated vaporisation and condensation in one pass and much higher strengths than a pot still.

The strengths at which the stillman switches the spirit-still run from foreshots to the middle cut, and from the middle cut to feints — thereby selecting which congeners enter the new-make spirit.

Heating a still by flame beneath the pot rather than by internal steam coils, producing localised hot spots and Maillard reactions in the charge that add roasted, toffee-like heaviness.

The weak, congener-heavy tail of the spirit distillation collected after the middle cut closes; rich in fusel oils, fatty acids and, in peated spirit, phenols. Retained and redistilled with the next charge.

The traditional method of germinating barley in a shallow bed on a stone floor, turned by hand with a shiel or malt plough to control temperature and stop the rootlets matting.

The first, highly volatile fraction off the spirit still — high in acetaldehyde, methanol and sulphur compounds — diverted away before the middle cut begins.

Drying green malt with heated air to halt germination and fix flavour and colour — the point at which peat smoke, if used, is introduced.

The pipe carrying vapour from the still's neck to the condenser. Its angle, length and diameter govern reflux: an upward slope returns more heavy vapour and gives lighter spirit, a downward slope gives heavier, oilier spirit.

The controlled steeping, germination and kilning of barley that develops the enzymes needed to convert starch to fermentable sugar, then arrests germination before the plant consumes the starch itself.

The recipe of cereals, by percentage of the grain charge, from which a whisky's mash is made — for example 75% corn, 13% rye, 12% malted barley.

The vessel in which grist is mixed with hot water so malt enzymes convert starch into fermentable sugars, and from which the sugary wort is drained off.

Unmatured spirit as collected from the spirit still and reduced for filling — typically 63.5% ABV in Scotland, and 55–62.5% ABV at barrel entry in the US.

Burning peat in the kiln so that phenolic smoke compounds — guaiacol, cresols, xylenols and phenol itself — adsorb onto germinated malt and carry through to the spirit.

The measure of peating intensity: total phenolic compounds in parts per million, determined by laboratory assay on the MALT — not on the spirit or the bottled whisky.

A batch still consisting of a heated pot, a swan neck and a lyne arm, in which each charge is distilled once and then emptied; its shape and operation determine reflux and hence spirit character.

Condensation of heavier vapour inside the still or lyne arm and its return to the pot for redistillation. More reflux gives lighter, cleaner, more floral spirit; less gives heavier, oilier, more sulphury spirit.

The standard modern condenser: a shell containing a bundle of copper tubes through which cooling water passes, condensing spirit vapour against a large copper surface area.

The near-universal American practice of adding a portion of spent, acidic stillage (backset) to each new mash to lower pH, discourage spoilage and promote consistent fermentation.

A sealed brass-and-glass box through which distillate flows so the stillman can observe strength and clarity and divert the flow between foreshots, spirit and feints receivers without touching the spirit.

The fermentation vessel — traditionally Oregon pine or larch, now often stainless steel — in which cooled wort is fermented by yeast into wash.

A traditional condenser: a tapering copper coil immersed in a tub of cold water, in which vapour condenses with minimal copper surface area per unit of vapour.

The sweet, unfermented sugary liquid drawn off the mash tun and cooled before yeast is pitched.

Strictly, the American Standard Barrel of approximately 200 litres (53 US gallons) used for bourbon and then widely reused for Scotch and Irish maturation.

A cask of approximately 500 litres, tall and comparatively narrow — the standard format for sherry-seasoned European oak in Scotch maturation.

The degree to which a barrel's interior has been burned to carbon before filling, graded by cooperages roughly #1 to #4 by exposure time — about 15 to 55 seconds. #4, the deepest, is 'alligator char'.

A cask being filled with whisky for the first time, having previously held something else — bourbon, sherry, wine or another spirit. It is not a new cask.

A cask of approximately 225–250 litres, in Scotch practice usually rebuilt from the staves of American Standard Barrels with extra staves and new ends — a fatter, larger cask made from bourbon wood.

Japanese oak, Quercus crispula, used for whisky casks since the Second World War: porous, difficult to cooper, prone to leaking, and characteristically contributing sandalwood, incense and coconut-lactone notes over long maturation.

A style of sherry fortified early to around 17% ABV so the flor yeast cannot survive, and therefore aged oxidatively. Casks seasoned with it contribute dried fruit, walnut, leather and colour.

A grape variety and the intensely sweet, sun-dried fortified wine made from it. PX-seasoned casks give raisin, fig and molasses along with marked sweetness and strong colour.

A short, wide cask of roughly 465–500 litres. Two forms are current: the 'machine puncheon' of thicker American oak used for rum and grain whisky, and the sherry-shape puncheon in European oak.

A small cask of roughly 125–140 litres, historically a quarter of a butt, whose high surface-area-to-volume ratio accelerates extraction and hence apparent maturity.

A cask on its second or subsequent fill with whisky, whose extractable wood compounds have been substantially depleted by earlier fills.

An exhausted cask returned to activity by physically removing the spent inner surface — shaving or scraping — and re-toasting or re-charring the fresh wood beneath.

Shaved, toasted and re-charred: a cask-rejuvenation protocol popularised by the late Dr Jim Swan in which a used cask's inner surface is shaved back to fresh wood, then toasted and lightly re-charred.

Slow heating of cask wood at lower temperature and for longer than charring, without carbonising the surface, degrading hemicellulose and lignin into vanillin, furfural and spice aldehydes.

A cask made from oak that has never previously held a liquid; called 'new oak' in US regulation.

Alcohol and water lost by evaporation through the cask during maturation — roughly 1.5–2% of volume a year in cool, humid Scottish warehouses, and often 3–5% in the first year in Kentucky's temperature extremes.

Maturation in two successive cask types where both periods are substantial — say ten years in ex-bourbon then eight in Oloroso — as distinct from a short finish on top of a long first maturation.

A secondary maturation period in a different cask type — sherry, port, wine, rum, virgin oak — after the main maturation, usually months to a few years, intended to layer character onto established spirit.

Holding a completed blend or vatting together — in a vat, or returned to inert or refill casks — for weeks or months before bottling, so the components integrate.

The quantity of pure alcohol in a cask when it was filled: bulk litres multiplied by strength at fill. Used as the baseline figure on cask purchase documentation.

The physical re-measurement of a cask in warehouse — weighing or dipping to establish bulk volume, and sampling to establish strength — to produce a current alcohol figure and revalue the contents.

The pure alcohol actually present in a cask at the date of its most recent regauge: current bulk litres multiplied by current strength.

A fractional-blending system borrowed from sherry, in which a vat is only ever partially emptied and is topped up with younger stock, so a small proportion of very old liquid persists indefinitely.

Chilling whisky to roughly 0 to −4°C and passing it through a fine filter to remove long-chain fatty acids, esters and proteins that would otherwise form a haze when the whisky is cooled or diluted.

Plain class I caramel, the only colouring permitted in Scotch, Irish and EU/UK whisky, used to standardise colour between batches. It is a colouring, not a sweetener or flavouring.

The persistence and evolution of flavour after the whisky is swallowed — its length, and whether it develops, holds or collapses.

The tactile, non-aroma dimension of whisky in the mouth: viscosity, oiliness, waxiness, astringency and warmth.

A voluntary claim that no caramel colouring has been added and that the whisky's colour derives solely from the cask.

The characteristic change in whisky held for decades in glass: a rounded, waxy, mineral, sometimes metallic profile with dampened fruit and heightened savoury notes, arising from very slow oxidation and ester rearrangement in a sealed system.

Progressive reaction of whisky with oxygen in the bottle headspace, flattening aromatic top notes and building cardboard, stale and faintly sour characteristics. It accelerates as the bottle empties and headspace grows.

A family of aromas — struck match, rubber, cabbage, drains, meat — arising from sulphur compounds, from insufficient copper contact in distillation, or from a cask over-treated with a sulphur candle.

Contamination by 2,4,6-trichloroanisole and related haloanisoles, giving damp cardboard, wet dog and musty cellar aromas and flattening fruit.

The volume of a scarce release apportioned by a producer to a market, distributor or retailer — and by extension the retail rationing that follows.

A warehouse approved by the tax authority for storage of goods on which duty is suspended; in the UK, an excise warehouse approved under the Customs and Excise Management Act 1979.

A percentage of the hammer price charged by the auction house to the buyer, commonly 10–30% in whisky auctions, and generally subject to VAT in its own right.

The document by which the owner of goods in a bonded warehouse instructs the warehousekeeper to transfer them, or title to them, to another party — the instrument by which casks in bond actually change hands.

The moment at which excise duty becomes payable — in UK terms, when goods are released for consumption, chiefly on removal from duty suspension. Until then goods sit 'in bond' with duty suspended.

A distillery that has closed and been dismantled ('ghost'), or one that has stopped production but could restart ('silent' or 'mothballed'). Remaining stock is finite and cannot be replaced.

The winning bid at auction, before buyer's premium, taxes and any charges are added.

A company that buys matured whisky from distilleries — in cask, in bulk or through brokers — and bottles it under its own brand, sometimes naming the distillery of origin and sometimes using a coded name.

Trade shorthand for a bottling carrying no declared age. It describes an absence, not a legal category — the whisky still meets the minimum maturation for its category: three years for Scotch and Irish, none at all for bourbon.

A release by the distillery or its brand owner, as opposed to an independent bottling; usually the core range plus limited and distillery-exclusive editions.

Resale of bottles and casks after first retail sale — through auction, broker or private trade — at prices set by demand rather than by the producer.

A bottling drawn from one individual cask rather than a vatting of several, normally identified by cask number and yielding a finite outturn.

A marketing term implying a bottling was assembled from a limited number of casks. It has no quantitative meaning.