Jargon File

At my first job in a research laboratory, the first thing that was handed to me was a sheet called the “Jargon File” and it was a list of unique words and acronyms specific to the job. That sheet of paper gave me a jump start into the job and every time someone used an acronym for a test or piece of equipment, I wasn’t lost, I knew exactly what they were talking about and my job performance was better for it.

Every industry has their word list and short-forms and without knowing these terms you can feel a bit out of place. To solve that problem, here is the jargon file for distilling. Look at it and refer to it as needed.

Distillation Jargon File

Alcohol: This is a collective term for many different compounds that fit into the alcohol category, like ethanol, the stuff we drink, methanol, the stuff we don’t and propanol, pentanol and others that can provide flavour to our spirits. 

Aldehyde: chemical compounds that often contribute negative aromas to distillate but are necessary for ester formation long term.

Attenuation: the degree to which yeast will consume the sugars in the wort or must. Low rates mean a low conversion to alcohol, which is inefficient for distillation purposes.

Azeotrope: a mixture of two or more liquids whose proportions cannot be altered or changed by simple distillation, in our case this will be the point where ethanol and water cannot be separated any further which is at 95.63% ethanol and 4.37% water-mark.

Backset: Commonly used in sour mashing techniques, backset is the spent liquid from a previous distillation run that is saved and then added to a new mash to add acidity.

Boiler: Where the liquid is heat; also a piece of equipment used to create steam

Condenser: Used to convert distillate vapours to liquid for collection. Can be an actively or passively cooled (air, water, etc.). 

Congener: A catch-all term for less desirable compounds in new make distillate

Diastase: A collective term for enzymes like amylase 

Ester: A pleasant, aromatic aroma compound composed of an aldehyde and an alcohol

Ethanol: the drinking alcohol we strive to purify in our distillation process

EtOH: a short form for ethanol

Eau de Vie: Literally means “water of life” but it refers to an unaged spirit, usually from fruit, like pears and grapes.

Feints: the undesirable last runnings of the distillation

Grist: ground or crushed grains


Ketone: a chemical compound, one of which is acetone, and usually associated with negative flavours, though some higher ketones do add positive flavours.

Lees: the remnants of yeast in the wort. Can add desirable flavours when included in the wash.

Likker: a trendy lowbrow term used by “moonshiners” and wannabe moonshiners to describe liquor.

Lyne Arm (Swan Arm): a tube that connects the head of a pot still to the condenser.

Marc: fresh, unaged distillate

Mash: the mixture of grains undergoing enzyme conversion 

Mashing: the art of converting grain starch into fermentable sugars

MeOH: a short form for methanol



Pot Ale:

Proof: Though measuring alcohol in degrees proof is antiquated and mostly abandoned, it is still used for marketing purposes and by people unwilling to accept change. Depending on where you live proof can mean different things. In the UK it was equal to 57.1% ABV and in the US it is 50% ABV.

Saccharification: the process of converting starches to sugar

Spirit Run: a second or third distillation in a pot still to refine the spirit.

Still Shock: a term to indicate the rough nature of fresh distillate. 

Stillage (see Backset): 

Stripping: this indicates a non-exact distillation to roughly separate some of the water. Often used to reduce the “bulk” of fermented liquids to save space. See Spirit Run

Tails: the third fraction of a distillation run that has a lower ABV and increased congener content. A less desirable cut, though small amounts can increase the flavour profile of the spirit.

Trays (see Plates): Used in columns to help fractionate the distillate

Wash: Also see Beer

Worm: a crude form of condenser, usually found in pot stills

Wort: the liquid extract from the mash containing fermentable sugars

Yeast: the biological engine that drives fermentation. A type of fungus that produces alcohol.