A device such as a stirrer that provides complete mixing and uniform dispersion of all components in a mixture. Agita tors are generally used continuously during the cooking process and intermittendy during fermentation.


The family name of a group of organic chemical com- pounds composed of carbon, hydrogen, and oxygen; includes methanol, ethanol, isopropyl alcohol, and others.


In its original meaning fermented hard apple cider that is partially frozen to separate the water from the alcohol. In modern terms it is the North American version of apple brandy.

Atmospheric Pressure

Pressure of the air and atmosphere surrounding us which changes from day to day. It is equal to 14.7 PSI.


A rotating, screwtype device that moves material through a cylinder. In alcohol production, it is used to transfer grains from storage to the grinding site to the cooker.

Baker’s Yeast

Standard robust yeast used openly by bakers, and quiedy by many distillers. The fermentation is quick and violent, and the resulting beer is cloudy. But that really doesn’t matter if you are going to distill it.


On a hydrometer, the measurement of the percent of sugar in a solution by weight. See Brix.


Varies depending on country. In U.S. terms, a liquid measure equal to 42 American gallons or about 306 pounds; one barrel equals 5.6 cubic feet or .159 cubic meters.

Batch Distillation

A process in which the liquid feed is placed in a single container and the entire volume is heated, in contrast to continuous distillation in which the liquid is fed continuously through the still.

Batch Fermentation

Fermentation conducted from start to finish in a single vessel.

Batch Process

Unit operation where one cycle of feed stock preparation, cooking, fermentation and distillation is completed before the next cycle is started.


Formerly the Bureau of Alcohol, Tobacco, and Firearms; under the U.S. Department ofTreasury. Responsible for the issuance of permits, both experimental and commercial, for the production of alcohol. The guns have been removed and the agency has been renamed the TTB, the Tobacco and Taxation Bureau.


A general term for all fermented malt beverages flavored with hops. A low level (6 to 12 percent) alcohol solution derived from the fermentation of mash by microorganisms. For distillers the initial fermented grain solution that is distilled. See Wash.

Beer Still

The stripping section of a distillation column for concentrating ethanol.


A unit based to heat water to produce steam for cooking and distillation processes.


Whiskey produced within the United States from a mash containing a minimum of 51% com and then aged for a minimum of two years in a new charred oak barrel. Bourbon can be legally produced in any state.


Generally speaking the result of distilling any fermented fruit wine. Specifically the result of distilling grape wine. Fruit Brandies are made from fruits other than grapes, while Fruit-Flavored Brandies are usually grape brandy with added fruit flavors. See Eau de Vie and Grappa.


Generically, the entire beermaking process, but technical- ly only the part of the process during which the beer wort is cooked in a brew kettle and during which time the hops are added. After brewing the beer is fermented. In a grain distillery the fermented wort or wash is frequendy referred to as beer.

Bubble-cap Trays

Cross flow trays usually installed in rectifying columns handling liquids free of suspended solids. The bubble caps consist of circular cups inverted over small vapor pipes. The vapor from the tray below passes through the vapor pipes into the caps and curves downward to escape below the rim into the liquid. The rim of each cap is slotted or serrated to break up the escaping vapor into small bubbles, thereby increasing the surface area of the vapor as it passes through the liquid.

Cane Spirit

The broad term for spirits distilled from fermented sugar cane juice. See Cachaca and Rum.


Unaged, raw sugar cane spirit from Brazil, usually mixed with neutral grain spirit from other sources.


By legal definition grape brandy from the Cognac region of France.


A vertical, cylindrical vessel used to increase the degree of separation of liquid mixtures by distillation or extraction.


A chemical term denoting a combination of two or more distinct elements.


The ratio of mass or volume of solute present in a solution to the amount of solvent. The quantity of ethyl alcohol (or sugar) present in a known quantity of water.


A heat transfer device that reduces a thermodynamic fluid from its vapor phase to its liquid phase.

Continuous Fermentation

A steady state fermentation system that operates without interruption; each stage of fermentation occurs in a separate section of the fermenter, and flow rates are set to correspond with required residence times.


A tank or vessel designed to cook a liquid or extract or digest solids in suspension; the cooker usually contains a source of heat; and is fitted with an agitator.


The process that breaks down the starch granules in the grain making the starch available for the liquefaction and saccharification steps.


The resulting substances and materials that accompany the production of ethanol by fermentation process.

Corn Whiskey (Likker)

Legally - Minimum 80% corn mash whis- key, aged a minimum of two years in used wooden barrels. Illegally - The fresh-from-the-still original version of Moonshine. See Moonshine.

Cross Flow Trays

Liquid flows across the tray and over a weir to a downcomer that carries it to the next lower tray. Vapors rise from the bottom of the column to the top passing through the tray openings and the pools of cross-flowing liquid.


The process of adding a substance to ethyl alcohol to make it unfit for human consumption; the denaturing agent may be gasoline or other substances specified by the Bureau of Alcohol, Tobacco, and Firearms.


To remove the free water from a solid substance.


That portion of a liquid which is removed as a vapor and condensed during a distillation process.


The process of separating the components of a mixture by differences in boiling point; a vapor is formed from the liquid by heating the liquid in a vessel and successively collecting and condensing the vapors into liquids.

Eau de Vie

Colorless fruit brandy such as Kirshwasser from the Schwartzwald in Germany.


The alcohol product of fermentation that is used in alcohol beverages and for industrial purposes; chemical formula blended with gasoline to make gasohol; also known as ethyl alcohol or grain alcohol.

Ethyl Alcohol

A flammable organic compound formed during sugar fermentation. It is also called ethanol, grain alcohol, or simply alcohol.


The conversion of a liquid to the vapor state by the addition of latent heat or vaporization.


A microorganically mediated enzymatic transformation of organic substances, especially carbohydrates, generally accompanied by the evolution of a gas. The process in which yeast turns the sugars present on malted grains into alcohol and carbon dioxide.

Gasohol (Gasahol)

Registered trade names for a blend of 90% unleaded gasoline with 10% fermentation ethanol.


A volatile, flammable liquid obtained from petroleum that has a boiling range of approximately 29-216 degrees Celsius and is used for fuel for spark ignition internal combustion engines.


White spirit flavored with juniper berry and other “botanicals.”


The end (enclosure) of a cylindrical shell. The most commonly used types of heads are hemispherical, ellipsoidal, flanged and dished (semispherical), conical and flat.


The initial run of distillate at the start of the distillation process. Heads are usually returned to the still for redistillation.

Heat Exchanger

A unit that transfers heat from one liquid (or vapor) to another without mixing the fluids. A condenser is one type of heat exchanger.


The dried blossom of the female hop plant, which is a climbing herb (Humulus lupulus). Aged hops are used by some whiskey distillers in the mashing process.


The process of straining wort in a lauter tun before it is cooled in the brew kettle.

Lauter Tun

The vessel used in brewing between the mash tun and the brew kettle. It separates the barley husks from the clear liquid wort. The barley husks themselves help provide a natural filter bed through which the wort is strained. This filtration is frequendy skipped in grain distillation.


A mixture, consisting of crushed grains and water, that can be fermented to produce ethyl alcohol.


The process by which barley malt is mixed with water and cooked to turn soluble starch into fermentable sugar. Other cereal grains, such as corn and rice, may also be added. After mashing in a mash tun, the mash is filtered through a lauter tun, where upon it becomes known as wort.

Methyl Alcohol

A poisonous type of alcohol, also known as Wood Alcohol. Produced as a byproduct of the fermentation of starch or cellulose. Methyl alcohol is not produced by fermenting sugar, and only minimally from fruit wine.


Distilled spirit from the pulp of the agave plant, produced in Mexico outside of the designated Tequila production area. See Tequila.


Originally minimallyaged corn whiskey produced illegally in the Appalachian Mountain region of the Southern United States. Modern Moonshine is usually made from fermented sugar water. See Corn Whiskey.


A hollow vessel more deep than broad.

Pressure Vessel

A metal container generally cylindrical or s pheroid, capable of withstanding various loadings.


The process by which a government prohibits its citizens from buying or possessing alcoholic beverages. Specifically, the Prohibition refers to the period between the effective date of the 18th Amendment to the US Constitution (16 January 1920) and its repeal by the 21st Amendment. Repeal took effect on 5 December 1933, although it passed Congress in February and the sale of beer was permitted after 7 April 1933.


Alcohol containing 50% Alcohol by Volume (ABV) is called 100 U.S. proof spirit. U.S. proof is twice the percentage of spirit by volume.


With regard to distillation, the selective increase of the concentration of the lower volatile component in a mixture by successive evaporation and condensation.

Rectifying Column

The portion of a distillation column above the feed tray in which rising vapor is enriched by interaction with a countercurrent falling stream of condensed vapor.

Rye Whiskey

Whiskey containing a minimum of 51% Rye grain, aged for at least two years in a new charred oak barrel. Rye Whiskey, which was the original whiskey in Colonial America, has a dry, hardedged palate, and is nowadays primarily blended into other types of whiskey to give them more character.


Structural element made to enclose some space. Most of the shells are generated by the revolution of a plane curve.

Shower Type Trays

These trays do not have downcomers. The liquid level results from the pressure drop caused by the counterflowing streams.

Sieve Trays

Sieve trays are usually cross flow type perforated with small holes. Sieve trays are sometimes used for feeds that tend to deposit solids or polymerize in the column.

Sight Gauge

A clear calibrated cylinder through which liquid level can be observed and measured.

Slobber Box

Pressure relief and particulate matter filter chamber located between the still and condenser coils on a pot still.


An apparatus for distilling liquids, particularly alcohols; it con- sists of a vessel in which the liquid is vaporized by heat, and a cooling device in which the vapor is condensed.

Stripping Column

The section of the distillation column in which the alcohol concentration in the starting beer solution is decreased. This section is below the beer injection point.

Stripping Section

The section of a distillation column below the feed in which the condensate is progressively decreased in the fraction of more volatile component by stripping.


A vessel of large size to contain liquids.


The final discharge of the distillation process, tails contain un- desirable flavor elements (congeners) and fusel oils, and are usually discarded.


Distilled spirit from the fermented pulp of the agave plant, produced by legal definition only in certain designated areas in and around the Mexican state of Jalisco. See Mezcai.

Tunnel Cap Trays

Tunnel cap trays are similar to bubble cap trays except that they are rectangular.

Valve Trays

Valve trays are cross flow trays with large perforations that are covered with flat plates. The cover plates are free to move vertically and thus permit the passage of ascending vapors.


The process of converting a compound from a liquid or solid state to the gaseous state. Alcohol is vaporized during the distillation.


A container or structural envelope in which material are processed, treated or stored; for example, pressure vessels, reactor vessels, agitator vessels, and storage vessels (tanks).


In U.S. terms, colorless, odorless, tasteless neutral spirit. Foreign Vodkas can retail flavor elements, particularly if pot-distilled.


In distilling, the liquid produced by the fermentation process, which is then distilled to concentrate the alcohol. See Beer.


Copper condenser coils suspended in a vessel of continuously flowing cold water, used as part of a pot still.


An oatmeal-like substance consisting of water and mash barley in which soluble starch has been mrned into fermentable sugar during the mashing process. The liquid remaining from a brewing mash preparation following the filtration of fermentable beer. In grain distillation the wort or mash is frequently fermented and then distilled without filtration.


The enzyme-producing one-celled fungi of the genus Saccharomyces that is added to wort before the fermenting process for the purpose of turning fermentable sugar into alcohol and carbon dioxide.