ABV: Abbreviation for Alcohol by Volume. In the US, proof is more typically used to denote strength of an alcoholic beverage. 50% ABV= 100 proof

Alligator char: the heaviest char level used by coopers when firing the inside of a new cask, which results in shiny, alligator-like “scaling” of the top-most surfaces of the wood. Also known as char level 4, the fire is passed through the center of the cask for approximately 55 seconds (Char #1 is 15 seconds, Char #2 is 30 seconds, and Char #3 is 35 seconds). Such a heavy char has tangible gustatory effects on the flavor imparted by the cask, added natural filtration of sulfuric compounds, coloration, and caramelization of wood sugars. 

American Standard Barrel (ASB): The most common cask in use today, the American Standard Barrel holds 200 liters, or 53 US liquid gallons. Typically made of American oak (quercus alba), though sometimes made from European oak (quercus robur), these casks are produced in the US and used first by the American whiskey industry before being exported all over the world to be used in the maturation of various spirits, like Scotch whisky, rum, tequila, wine, and much more. 

Angel’s Share:  denotes the quantity of distilled spirits lost to evaporation while ageing in wooden casks; and/or the vapors resulting from this process. See one of the first references to this by clicking here.

Attenuation: The conversion of soluble sugars in the fermentation process to ethyl alcohol.

Backset: Backset is the liquid left in the still after the alcohol has drained off (not to be confused with feints or foreshots) and is often collected and added to the next run in a process known as “sour mashing”.  In the sour mashing process, adding the backset to the mash in the next run can set the PH level, reduce needed energy expenditure, and contribute to flavor. 

Barrique: Widely used by the cognac and wine industry, these large hogshead-shaped casks have a capacity for 300 liters, or 79 US liquid gallons. Often used for secondary maturation in the whisk(e)y community.

Bottled-in-bond: In the late 1800’s, unscrupulous entrepreneurs were making a quick buck selling counterfeit spirits labeled as whisk(e)y. Under pressure from the distilling industry led by Colonel Edmund Haynes Taylor, Jr., the US government passed The Bottled-In-Bond Act of 1897, which granted control of access to bonded warehouses to treasury agents. To be labeled as “Bottled-in-Bond”, all spirits in the bottle must have been:

• distilled in the same distilling season
• distilled at a single distillery
• Aged for a minimum of four years in a government-supervised warehouse
• Bottled at 100 proof
• The label must identify the real name of the distillery where it was made
• The label must identify the bottling location (if different than the distillery)
• Only water could be added

The presence of the green Bottled-In-Bond tax stamp gave Americans assurance of quality, purity, gave producers a tax incentive for participating, and also ensured the proper taxes were being collected. It became recognized as one of the very first consumer protection acts enacted in US history.  While most Bottled-in-Bond spirits today are bourbons, the designation is also used by rye whiskey, corn whiskey, and apple brandy.

British brewery barrel: A standard measure and cask size used in the British brewing industry. A British brewery barrel has the capacity for 164 liters, or 43 US liquid gallons, or 288 pints.

Cask Finishing, or Secondary Maturation: The practice of moving a whisk(e)y from its original cask into another cask of a different style for short period before decanting. The second cask may have been used to mature another spirit like rum or sherry. The finishing cask can impart some element of flavor, color, or even texture to a whisk(e)y. This practice has been in use in Scotland since the late 80’s and is often credited to the ingenuity of both David Stewart of The Balvenie and Dr. Bill Lumsden of The Glenmorangie. 

Cask Seasoning: Also called “envinado” in Spain, a new industry has grown around the seasoning of new casks with sherry wine to accommodate the massive demand from the whisk(e)y industry. New casks are “treated” with a sherry wine according to the distillers’ specifications, usually oloroso or Pedro Ximenez for as long as three years. The sherry wines used in this process are not suitable for drinking and are often redistilled for Spanish brandy.

Chill-filtration: The process by which a whisk(e)y is chilled to promote the solidification of fatty acids and then run through a filtration screen. This can be a contentious point of quality with many whisk(e)y lovers….

Coffey Still: A type of column still capable of continuous distillation invented by Irishman Aeneas Coffey in 1830.

Column Still: A tall cylindrical still style capable of continuous distillation, as opposed to the pot still, which needs to be operated in runs.  Column stills are commonly used in the American whisk(e)y industry but cannot be used in the Scotch industry according to Scottish law. Column stills are industrially more efficient for distillation but produce a more uniform spirit (in most cases.) Many distilleries today utilize a combination or hybrid Pot/ Column still. 

Control state: Seventeen states in the US in which the state controls one or more tiers of the three-tier system. often, the state employs a Liquor Control Board, who in turn operates state-run liquor stores.  

Cooper: Coopers (trabajaderos in Spain) are the craftsman who make and service oaken casks. The word comes from Latin, l. Cupa. Coopering is a skilled craft, only learned through a 4-year apprenticeship in the service of a master cooper. One of the final tests in a journeyman cooper’s training is to make a functional firkin cask. 

Dephlegmator: Sometimes known as a reflux condenser, a dephlegmator (Pronounced duh-fleg-mater) is an attachment used by many modern distillers that sits at the top of the column still. The dephlegmator is filled with a network of tiny tubes that are cooled with water to promote condensation of alcoholic vapors, dropping the liquid back down into the column. Often, column stills utilize a series of plates that allow vapor to pass upwards but stop liquids from passing downwards. These liquids are essentially re-distilled, and lighter flavors and esters can become more focused. Thereby a distiller can achieve a more complete separation of the components of a distillate. However, too much reflux and any notable flavors can be lost! (Wonderful, if you’re making vodka!)

Distillers’ Caramel: According to the Scotch Whisky Law of 2009, only water and distillers’ caramel can be added to whisky. This substance is produced by burning sugars to create a dark colored syrup of various shades. The most commonly used distillers’ caramel is E150a. This product is ostensibly used to establish consistency between batches, but some argue that the practice is misleading. In the US, no color is allowed in the production of straight bourbons that does not come directly from maturing in a charred cask. Other whisk(e)y producing nations have their own laws governing the use of distillers’ caramel.  

Exogenous enzymes: Enzymes used in the fermentation process that did not originate with the cereal grains in the mash. Often used in 100% Rye mash-bill whiskies, as well as whiskies made with roasted grains. 

Fermentation: The process in which yeast is added to the wort and begins to convert the fermentable sugars into heat and alcohol to produce the simple beer we call the “wash”. It should be noted that this is the step in the spirits-making process in which alcohol is created- and at the same time to note that the distillation process only separates out that alcohol. Fermentation is vital to the ending character of the whisk(e)y- a slower fermentation results in earthier flavors. 

Firkin: A quarter the size of the British brewery barrel, the firkin holds 41 liters, or 11 US liquid gallons. Commonly used in the home brewing industry for the maturation of cask ale. Making a functional firkin is how an apprentice cooper demonstrate that he/she has successfully honed their craft before ending their apprenticeship.

Flocculation: Flocculation refers to the ability of yeast to aggregate and form large flocs and then drop out of suspension. The definition of flocculation is, “reversible, asexual and calcium dependent process by which cells adhere to form flocs.”

Grain Neutral Spirits: Spirits distilled from a fermented mash of grain at or above 95% alcohol by volume (190 proof), and if bottled, bottled at not less than 40% alcohol by volume (80 proof).

Heads or Foreshots: The first liquids to emerge from the condensers at the spirit safe are full of the most volatile compounds with the lowest boiling points, like methanol, acetaldehyde, sulfur compounds, and ethyl esters. They also can carry any impurities from the lyne arm left from the tails of the previous run. These liquids are not desirable nor safe to consume. At the spirit safe, the distiller can direct these heads or foreshots to the feints receiver, often to be redistilled. 

Heart: At the end of the foreshots, the distiller can make a cut, directing the “heart of the run”, or the desirable ethanol spirit to the intermediate spirits receiver. This is the portion of the run which will be matured to become whisk(e)y, showcasing the distiller’s desired flavors and aromas.  The heart of the run in a whisk(e)y distillery is also known as “new make”, or “white lightning”, or “moonshine”.

Hogshead:  Scotch whisky distilleries often break down 5 American Standard Barrels (53 gallon) and reconstruct them using new cask heads to build 4 hogsheads. The origin of this name is most likely derived from an English term used in the 1600’s; “Hogges hede”, which was a large cask able to store 63 Imperial gallons. Modern hogsheads used in the whisk(e)y industry hold 54 Imperial gallons, or 64 US Liquid gallons.)

Kilderkin: From the Dutch word for “small cask”, A kilderkin is a type of cask with a capacity for 82 liters, or 22 US liquid gallons. Often used in the brewing industry, a kilderkin is equivalent to half a British brewery barrel, or two firkins.

Lactones:  Oak lactones, (cis- or trans-) are isomers that play a major role in the aromas and flavors extracted from oak casks during maturation. Quercus Alba, or American White Oak generally have higher concentrations of cis-lactones, imparting the recognizable notes of coconut, celery, and wood. Careful seasoning of the oak staves can affect the ratio of cis- and trans-lactone, while toasting a cask can reduce oak lactones. 

Legs: The “legs” of a whisk(e)y can be observed my gently swirling whiskey in a clear glass and observing how the liquid clings to the inside surface of the glass, and how long it takes to run back down to the bottom of the glass. To the trained eye, it can indicate alcohol content in a spirit. This phenomenon is due to the surface tension registered between the alcohol and the water contained in the whisk(e)y. This is also observable is wine, (called the “tears”) and is known as the Marangoni Effect, named for the Italian physicist Carlo Marangoni. 

Light Whiskey: or American light whiskey is a category which emerged onto the scene in 1968 in producer’s efforts to stem the tide of consumers towards spirits with lighter flavor profiles. Light Whiskey is distilled to at least 160 proof, though they are often distilled to 190 proof.  They are then aged in used or uncharred oak barrels, which imparts lighter color to the final spirit. While this experiment never really caught on in the 70’s, recently distillers have explored its potential for entry level whiskey drinkers.  

Lignans:  are polyphenolic compounds found in plants, particularly seeds, whole grains, and vegetables. The name derives from the Latin word for “wood”. During barrel aging, spirits undergo organoleptic changes caused by the release of aroma and taste compounds, including the bitter properties of oak wood lignans. 

Louching: The solidification of fatty acids in cold temperatures, which sometimes has the effect of making a whisk(e)y appear cloudy or hazy. An indication on non-chill-filtration

Low Wines: A liquor containing about 20 percent alcohol, produced by the first distillation of wash; the first run of the still

Lyne arm: At the top of a pot still, a long sweeping length of copper tubing that extends at a variable angle before emptying into the condensers. The angle of a lyne arm can be manipulated to increase or decrease reflux.  

Mashbill: The often proprietary “recipe” of grains used by distillers in the American whiskey industry. Mashbills often determine the style of whiskey being made. 

Monongahela Rye: The Monongahela River winds its way slowly from West Virginia to Pittsburgh, where it merges with the Allegheny to become the Ohio River. Farmer-distillers working the Monongahela Valley grew rye and distilled the surplus into a regional style of whiskey. Monongahela rye was the first American whiskey style to gain widespread recognition. It grew in considerable notoriety due to the Whiskey Rebellion. Old Monongahela style rye is distilled from rye and barley, usually in a ratio on 4:1, and using a traditional three-chamber still.

Port Pipe:  Typically made from Quercus Robur (European White Oak), Port pipes have a capacity for 650 liters, or 172 US liquid gallons. As their names would suggest, they are both long and slender, and used traditionally to age Port wine. Widely used in the Scotch Whisky industry for secondary maturation. 

Prohibition: America’s “Great Experiment”, passed as an amendment in 1920 which banned the production, sale, and consumption of alcoholic beverages in the United States, except in very limited fashion and for medicinal purposes. Prohibition lasted for 13 years before the passing of The Volstead Act.

Puncheon:  A short fat cask with a capacity for 500 liters (or 123 US Liquid gallons) made from thick staves of American or European Oak. Puncheons are commonly used in the rum, whisk(e)y, and sherry industry. 

Quarter Cask: As the name would suggest, these casks are built to be 1/4 the size of the ASB, but to precisely the same proportions. A quarter cask can hold 50 liters, or 13 US liquid gallons. The smaller size of these casks leads to a great interaction of liquid to wood, due to an increased surface area contact. Whisk(e)y can mature rapidly in these diminutive casks, though sometimes less predictably than in traditional larger casks. 

Reflux: Only the lightest vapors rising from the spirit still make it over the lyne-arm. The heavier vapors will re-condense in the swan neck and drop back down into the still, effectively to be re-distilled. This results in lighter and grassier flavors being emphasized. Some stills are equipped with a high-sloping lyne-arm to promote greater reflux in the distillation process.

Rundlet: A small archaic cask type of no certain dimensions, usually equivalent to 1/14 of a tun

Shell-and-Tube Condenser: Invented by William Grimble in 1825, the shell-and-tube condenser is a heat exchange system in which 100 or more copper tubes through which cold water can flow are bundled within a copper shell. As alcohol vapor passes through the shell and meets the cold tubes, it condenses. In the late 19th century, most distilleries replaced the more traditional worm tub condensers with shell-and-tube condensers, which are easier and more cost-effective to maintain. Using a shell-and-tube condenser usually results in a lighter and more uniform spirit, but not always…

Sherry butt: or Botas, are the casks used to mature sherries in Southern Spain. Large and slender, these casks are often made of Quercus Alba, or American White Oak. Larger in size than the American Standard Barrel, Sherry butts have a capacity for 500 liters, or 132 US liquid gallons. The sherry industry is not seeking wood influences in the aging of sherry wines, so these casks are often in service for as long as a century. Sherry makers often replace broken or leaky staves with used wood from a large stockpile of old staves and hoops, as new components would affect the flavor of the wine. Sherry butts are usually treated with an inert black paint, which makes it easier for arrumbadors (highly skilled cask repair craftsman) to spot leaks or compromised staves. 

Spirit still: The second still used in pot distillation, into which the low wines (21-30% ABV) are distilled. While this process is relatively similar to the first distillation, since there are no solids in the spirit still after the first distillation, sight windows aren’t necessary on the spirit still. Running for approximately 6 hours, the spirit still further separates out water from the alcohol. After the vapors finally rise over the lyne arm for the last time, they are condensed again before feeding into the spirit safe at approximately 70% ABV. 

Straight: A bourbon whiskey can be a bourbon, but to be labeled as “Straight Bourbon”; it must be aged in charred new oak containers for a minimum of two years.  “Straight Bourbon Whisky” can include a mixture of two or more straight bourbon whiskies, provided all of the whiskies are produced in the same state. If the whiskies originate from different states, the whiskey must be labeled as either “A blend of straight bourbon whiskies”, or “blended straight bourbon whiskies”.

Thief or Valinche: A cylindrical tube typically made of copper used to draw whisk(e)y from a cask for sampling. 

Tails or Feints: At a certain point into the heart of the run, the distiller will note a change in aroma and character of the spirit and determine when to make the cut into the “tails” or “feints” of the run. The tails emerge from the condensers containing the heaviest, oiliest, and least volatile compounds. Like the foreshots, the tails are not desirable nor safe to consume. When the distiller cuts away from the heart of the run, he can direct the feints to the feints receiver to be mixed with the foreshots, often to be redistilled in the next run.  

Tun: or “English Tun” is a huge cask, with a capacity for 982 liters or 259 US liquid gallons. Under Scottish law, tuns are too large to mature Scotch whisky. However, they are often used to marry whisky when blending. (See: The Balvenie Tun Series by clicking here. An English tun is equivalent to 2 butts, or 4 British Brewery barrels. 

Malting: The process by which a cereal grain is encouraged to break down protective cell walls, making its enzymes and sugars available to participate in the fermentation process when introduced to yeast. This is accomplished by germination of the grain seed through endothermic hydration, and then arresting development by kilning. The end product is known as malt. 

Moonshine or New Make: Whisk(e)y before maturation in oak casks is called “moonshine”, “white dog”, or “white lightning” in the USA, and “new make” in Scotland, Ireland, and Japan.

Malting floor: long rooms with perforated floors where the barley is spread after steeping. The malting floor is raked and turned evenly while heat is applied from kilns under the floor to arrest the endosperm’s development. Peat can be burned in the kilns as well to impart phenolic compounds during the malting process. Only 9 distilleries in Scotland still maintain malting floors. Modern maltsters utilize large rotating drum malts, which are faster and more efficient and less labor intensive than the more old-fashioned malting floor.

Peat: Organic material such as vegetation subjected to decomposition and pressure in an anaerobic environment such as a bog, fens, or swamp over the course of several thousand years. Peat bogs are natural carbon sinks, absorbing CO2 and preserving balance in wetlands. Over time, the formation of peat the first step in the geological formation of fossil fuels such as coal, particularly low-grade coal such as lignite. Peat has been used for the heating of homes and cooking in both Scottish and Irish homes for thousands of years. It is also used by whisk(e)y distilleries as a part of the kilning process when malting barley. 

Second-fill: A cask used for the second time. Many second-fill casks were first filled for bourbon. Each time a cask is used, oak lactones, vanillins, tannins, and more compounds have been reduced. These casks are widely used by the Scotch industry, as whiskies can be matured somewhat predictably in second-fill cask.

Shot grain: the colloquial term for a barley seed growing into a new barley plant on the malting floor, due to its development not being sufficiently arrested.

Small grains: While many whisk(e)y styles like bourbon require the majority of the grain to be one cereal (such as corn), the small grains refer to the often proprietary “recipe” of other grains used. 

Tax stamp: A green strip of paper added to neck of Bottled-in-Bond products; demonstrating that the spirits were aged in a bonded warehouse under government supervision; an assurance of quality. 

Three-tier system: In the US, the sale and distribution of alcoholic beverages must follow this system. Products flow from suppliers to licensed distributors, who in turn sell to retailers both in the on- and off-premise, from whom consumers can purchase. The three-tier system is active in most of the states, with the remainder being designated “control states.”

Virgin Oak: A brand-new cask, never previously used to store whisk(e)y. By law, Bourbon must be matured in a charred, virgin oak cask.

The Volstead Act: The Eighteenth Amendment banned but did not define “intoxicating liquors.” Some of the members of Congress who had voted for the amendment assumed that it referred to hard liquor and would exempt beer and wine. But the head of the Anti-Saloon League drafted a tough enforcement act, which was then sponsored by the chairman of the House Judiciary Committee, Minnesota representative Andrew Volstead. The National Prohibition Act, better known as the Volstead Act, defined an intoxicating beverage as anything that contained more than one half of one percent alcohol. By contrast, Canadian prohibition laws set the limit at 2.5 percent. The Volstead Act made it illegal to “manufacture, sell, barter, transport, import, export, deliver, furnish, or possess” such beverages. When it was ratified in 1920, the United States entered the Prohibition era.

Wash still: The first still used in pot still distillation, which is filled about 3/4 full of the beer from the washback (7-8% ABV). Most wash stills are heated with a length of copper tubing through which steam can be passed. Some still utilize direct heat of the wash still by wood or gas fire. Wash stills often can be identified by the one or more glass windows (sometimes) present on the still neck, allowing the still man to watch for boil-over. The initial distillation can last for approximately 4-6 hours, after which the low wines pass over the lyne arm, condensed, and collected in the spirit still at roughly 21-30% ABV to be distilled again. 

The Whiskey Rebellion:  In January 1791, President George Washington’s Secretary of the Treasury Alexander Hamilton proposed a seemingly innocuous excise tax “upon spirits distilled within the United States, and for appropriating the same.”  What Congress failed to predict was the vehement rejection of this tax by Americans living on the frontier of Western Pennsylvania. By 1794, the Whiskey Rebellion threatened the stability of the nascent United States and forced President Washington to personally lead the United States militia westward to stop the rebels.

Worm tub: Invented in Germany circa 1540 (though the modern worm tub as we now know it was based upon the 1771 design of Christian Weigel) and in use at the more traditional distilleries, a worm tub condenser is a long length of metal tubing coiled (resembling the coils of a serpent, or wyrm) immersed in cold water through which alcohol vapor would pass after dropping over the lyne arm. More costly and laborious to maintain, worm tub condensers tend to leave more robust and “meaty” character in a whisk(e)y due to various factors, such as the speed at which the stills are run and the reduced copper contact in comparison to the shell-and-tube condenser.  Many distilleries have replaced worm tub condensers with the modern shell-and-tube condenser. However, some distilleries opt to stay with the worm tub, unwilling to part with the complexity it can add to a whisk(e)y.

Wort: After mashing, and before fermentation, our starting point for making whisk(e)y. The character of a whisk(e)y can be very different if a distiller chooses either to start off with a crystal-clear wort or with a cloudy wort.