A–M

Alembic
A traditional pot-still design, often made of copper, used for batch distillation since antiquity; its curved neck and arms help concentrate and direct vapor toward the condenser.
Amylase
An enzyme, naturally present in malted grain, that breaks down starch into fermentable sugars during mashing.
Backset
The stillage left over after a distillation run, sometimes recycled into a new batch as part of the sour mash process to stabilize acidity and flavor from batch to batch.
Barrel Char
The layer of burnt wood inside a barrel's interior, created by torching the staves, which filters spirit through a layer of activated carbon and adds color and vanilla, caramel, and smoke notes.
Beer Well
A holding tank where fermented wash is stored after fermentation and before it is pumped to the still for distillation.
Brix
A scale measuring the sugar content of a liquid such as grape must or fermenting wash, used to estimate potential alcohol before fermentation begins and to track how fermentation is progressing.
Bung
The stopper, traditionally wooden, driven into the hole of a barrel to seal in maturing spirit.
Column Still
A continuous-distillation still built from a series of stacked plates that produces a lighter, more refined, higher-proof spirit than a traditional pot still, and can run around the clock.
Congeners
Flavor- and aroma-active compounds, other than ethanol and water, produced during fermentation and aging; they are largely responsible for a spirit's character and can also contribute to hangover severity.
Cooperage
The craft of building and repairing wooden barrels, or the workshop where that craft takes place.
Cut
The point in a distillation run where the distiller switches from collecting one fraction to the next, such as from heads to hearts, a judgment call that shapes the final spirit's quality.
Diastatic Power
A measure of a grain's enzyme activity, indicating its ability to convert its own starches into fermentable sugar; malted barley is prized in part for its especially high diastatic power.
Distillate
The concentrated alcohol liquid produced by distillation, before any aging, dilution, or filtration is applied to turn it into a finished, bottled spirit.
Doubler
A secondary pot still, connected directly to a column still, used after a first distillation run to further concentrate and refine the spirit in a single continuous process.
Esters
Aromatic compounds formed during fermentation that contribute fruity notes, such as banana, pear, or tropical fruit, to spirits and beer, depending on the yeast strain and fermentation temperature used.
Ethanol
The specific type of alcohol produced by fermentation and concentrated by distillation, and the active ingredient in all alcoholic drinks.
Fermentation
The process by which yeast converts sugar into alcohol and carbon dioxide, forming the base wash or wort that will later be distilled or bottled as beer or wine.
Filtration
Passing a finished spirit through a filter medium to remove particles, and sometimes fats, before bottling.
Fusel Oils
Higher alcohols produced during fermentation that add weight and character to a spirit but can taste harsh, oily, or solvent-like when present in excess, which is one reason distillers separate cuts.
Grain-to-Glass
A production model in which a distillery mashes, ferments, distills, and bottles its own spirit entirely on site, rather than sourcing bulk distillate produced elsewhere.
Heads
The first, highest-proof fraction collected during distillation, often discarded or redistilled because it can carry harsh, solvent-like compounds such as acetone and methanol.
Hearts
The middle fraction of a distillation run, prized for its clean flavor and balance, and typically the only portion of the run that is bottled as finished spirit.
Hybrid Still
A still that combines a pot still's kettle with a column still's rectifying plates, offering a distiller more control over the finished spirit's character.
Kiln
The chamber where malted grain is dried with heated air, sometimes fired with peat, stopping germination and setting the grain's color and flavor.
Low Wines
The relatively low-proof spirit produced by a first distillation run, which is redistilled a second time to raise its strength and refine away unwanted flavors.
Lyne Arm
The pipe connecting a pot still's neck to its condenser; its angle affects how much reflux and copper contact the vapor gets before condensing.
Maltster
A person or company that malts grain, controlling germination and kilning to prepare it for brewing or distilling.
Mash Bill
The recipe of grains used to make a spirit, expressed as percentages (e.g. corn, rye, malted barley), which is one of the biggest drivers of a whiskey's final flavor.
Mash Tun
The vessel in which grain is mixed with hot water to convert starches into fermentable sugars before fermentation.

N–Z

Neutral Spirit
A highly distilled, nearly flavorless spirit, typically bottled around 190 proof, used as a base for vodka, gin, and many liqueurs.
New Make
Unaged spirit straight off the still, clear and often fiery, before it goes into a cask to become whisky or brandy.
Oak
The wood most commonly used for aging barrels, prized for the vanilla, spice, coconut, and tannin it lends to spirit, with different oak species producing noticeably different flavor profiles.
Overproof
A spirit bottled at a notably higher ABV than the standard 40%, often 50% or more, common in certain rums and some whiskies.
Pagoda
The distinctive pointed, ventilated roof historically built over a distillery's kiln to draw smoke and heat up and out during malting.
Pot Ale
The residual liquid left in a pot still after distilling the wash, sometimes processed into animal feed or fertilizer.
Pot Still
A traditional, batch-based still that typically produces a more flavorful, less refined spirit than a column still, requiring the still to be emptied and reloaded after each run.
Proof
A measure of alcohol strength; in the U.S., proof is double the ABV percentage, so an 80-proof spirit is 40% alcohol by volume.
Quarter Cask
A small barrel, roughly a quarter the size of a standard barrel, used to speed up maturation through its higher wood-to-spirit ratio.
Racked Warehouse
A modern, multi-story warehouse where barrels are stored on steel racking rather than stacked directly on the floor as in a dunnage warehouse.
Rectification
Additional distillation intended to increase a spirit's purity and proof, removing more congeners with each pass and generally producing a lighter, cleaner-tasting spirit.
Reflux
The condensation and re-boiling of vapor inside a still, which increases the number of effective distillations and yields a purer, higher-proof, but often less flavorful spirit.
Rickhouse
A warehouse used to age barrels of spirit, sometimes built several floors tall so distillers can exploit the temperature swings between upper and lower levels.
Solera
A fractional blending system, developed for sherry and also used for some rum and whiskey, in which younger spirit is added to partially emptied older barrels.
Sour Mash
A production method using a portion of a previous batch's spent mash to start fermentation on the next, stabilizing pH and helping maintain a consistent flavor from batch to batch.
Spent Grain
The leftover grain solids remaining after mashing, once their sugars have been extracted, commonly repurposed as livestock feed.
Spirit Safe
A locked, sealed glass cabinet through which distillate flows during a run, letting a distiller monitor proof and separate the cuts by sight and smell without ever touching the spirit.
Stripping Run
A first, fast distillation pass intended mainly to concentrate alcohol quickly rather than to refine flavor, with the resulting low wines distilled a second, slower time to finish the spirit.
Tails
The final, lowest-proof fraction of a distillation run, often oily, vegetal, or musty in character, and usually discarded or set aside for redistillation.
Thumper
A secondary vessel connected between a pot still and its condenser that re-boils passing vapor, effectively adding an extra distillation without a second full still run.
Toasting
Exposing barrel staves to gentle, controlled heat before assembly, developing sugars and flavor compounds in the wood short of the deeper burn produced by charring.
Vatting
Blending spirit from multiple casks together, typically of the same type and age range, before bottling to even out variation between individual barrels.
Warehouseman
The worker responsible for managing a distillery's aging warehouse, including monitoring casks, rotating stock, and tracking evaporation.
Wash
The fermented liquid, similar to a low-alcohol beer, that is distilled to produce spirit; its quality has a direct effect on the character of the final product.
Water Cut
The addition of water to a matured spirit before bottling, gradually lowering it from cask strength down to its final, labeled proof.
Wort
The sugary liquid extracted from malted grain before fermentation, which yeast later converts into beer or, once distilled, into whiskey.
Yeast Pitch
The point at which yeast is added to a fermenter to begin converting sugars into alcohol, with pitching rate and temperature both affecting the final flavor.
Yield
The amount of alcohol a distiller can extract from a given quantity of grain or other raw material, a key measure of production efficiency.
Zymase
The enzyme complex within yeast that actually carries out fermentation, converting simple sugars into ethanol and carbon dioxide.
  • Glossary
  • Production

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