Interested in distilling but not sure what all that jargon means? Well, we're here to help! Let's take a look at some of the terminology you might come across in your home distillation journey.
Glossary of the key terminology used whilst making spirits:
- Alcohol (or ethanol) - Most used to describe ethanol, the type of alcohol in wine, beer, spirits, and other alcoholic beverages. It has the chemical formula C2H5OH.
- Wash - Fermented liquid containing alcohol which has been produced by yeast fermenting sugars.
- Fermentation - Conversion of carbohydrates (sugars) into alcohol, heat, flavour compounds, and CO2 by yeast.
- Saccharomyces - The genus of single-celled yeasts that ferment sugar and are used in the making of alcoholic beverages and bread.
- Yeasts - Yeasts are microorganisms that convert sugar to produce alcohol and CO2 along with hundreds of trace by-products.
- Yeast Pitching - The point in the process in which yeast is added to cool wash prior to fermentation.
- Enzymes – Fungal (glucoamylase) or bacterially derived (alpha amylase) enzymes for converting gelatinised starch and dextrins into simple sugars.
- Mashing - The process of mixing crushed malt (and possibly other grains or adjuncts) with hot water to convert grain starches to fermentable sugars and non-fermentable carbohydrates.
- Nutrient - Yeast nutrient blends especially formulated for optimal congener production during fermentation.
- Congener - The name given to all compounds in the distillate, other than water and alcohol. Congeners contribute to taste, aroma, and mouth feel.
- Hydrometer - The hydrometer is a tool used to measure the specific gravity and monitor wash fermentation; it tells how much sugar has been transformed into alcohol.
- Specific Gravity (SG) - The ratio of the density of a substance to the density of water. This method is used to determine how much dissolved sugars are present in the wash. Specific gravity has no units because it is expressed as a ratio.
- Original Gravity (OG) - The specific gravity of a wash before fermentation. A measure of the total amount of solids that are dissolved in the wort as compared to the density of water, which is conventionally given as 1.000 and higher. Synonym: Starting gravity; starting specific gravity; original wort gravity.
- Distillation - Method of separating a mixture of two or more substances based on their boiling or freezing point.
- Distillate - The concentrated and separated liquid that comes from the distillation process.
- Alcohol Purity - Alcohol purity describes the strength of the alcohol; it is measured in percentage of alcohol by volume or % ABV.
- Alcometer - Alcometers are a tool used to measure the percentage of alcohol in your spirit.
- Alcohol Yield - Alcohol yield describes the effectiveness of alcohol extraction from the wash. The higher the yield the less alcohol is left behind in the boiler.
- Stripping run - The stripping run is done first and 'strips' the wash down to a cleaner, more concentrated low wine. The purpose of a stripping run is to capture as much distillate from the wash as possible as quickly as possible.
- Solvent - flavour and aromatic character similar to acetone or lacquer thinner, often due to high fermentation temperatures.
- Spirit run - The spirit run is a more controlled distillation using the diluted product of a stripping run. This process involves the separation of the distillate coming from the still into different cuts to maximise flavour and yield of the final spirit.
- Cuts – The process by which distillate is separated as it comes off the still based on its composition of positive and negative congeners. The separated cuts are then either blended or discarded based on the flavour to result in the final spirit.
- Foreshots – the first cut of the spirit run. This section contains more harmful components of the spirit typically the first 50-100 mL of distillate from a standard wash and is always discarded.
- Heads - The name given to the first portion of distillate collected from a spirit run. They are composed of the lower boiling point congeners which have a distinctive ‘fruity’ or ‘nail polish’ smell.
- Hearts - The middle portion of the spirit run, and typically the most neutral and cleanest part of the run.
- Tails - The name given to the last portion of distillate collected. They are composed of oily congeners, responsible for mouthfeel, slickness or burnt flavours.
- Feints - This comes in the end of the tails cuts and is not necessarily bad but is not refined enough to use in your final spirit. It can be discarded or saved for future runs to boost yield.
- Methanol - An alcohol naturally produced during fermentation at a very low level (0.0005%). Its chemical formula is CH3OH. In large doses methanol is toxic. However, by discarding the recommended level of foreshots, the final spirit will have a very low percentage of methanol present.
- Activated Carbon/Charcoal - Activated carbon is prepared in a manner which causes the carbon crystals to become porous and develop a very large surface area. This large surface area and the many internal pores in the carbon can adsorb many different flavours and aroma from your spirit.
- Spirit - An alcohol beverage containing at least 20% ABV with no added sugar.
- Spirit Flavouring (essence) - flavourings that can be added to distilled neutral spirits or vodka to emulate the desired spirit type.
- Botanicals - Plant-based materials used in distilling to infuse flavour. Also used when producing essential oils.
- Dark Spirit - Typically spirits that have been produced by a pot still and barrel aged. E.g. whiskey, bourbons, rum (non-white), tequila, brandy and cognac.
- Light Spirit - Spirits produced in either a reflux or pot still that are not barrel aged. E.g. Gin, vodka, white rum, tequila blanco.
- Fusel Alcohol - A family of high molecular weight alcohols, which result from excessively high fermentation temperatures. Fusel alcohols can impart harsh or solvent-like characteristics commonly described as lacquer or paint thinner. It can contribute to hangovers.
- Final Gravity - The specific gravity of a wash as measured when fermentation is complete (when all desired fermentable sugars have been converted to alcohol and carbon dioxide gas). Synonym: Final specific gravity; final SG; finishing gravity; terminal gravity.
- Filtration - The passage of a liquid through a permeable or porous substance to remove flavours or solid matter in suspension.
- Air Lock - A one-way valve, often made of glass or plastic that is fitted onto a fermenter and allows carbon dioxide gas to escape from the fermenter while excluding ambient wild yeasts, bacteria and contaminants.
- Fermenter – A vessel that can be sealed with an airlock for the purpose of fermenting a wash.
- Carboy - A large glass, plastic or earthenware bottle. Often used as a fermenter or spirit storage vessel for ageing.
- Attenuation - The reduction in a wash's specific gravity caused by the yeast consuming wort sugars and converting them into alcohol and carbon dioxide gas through fermentation.
- Alcohol by Volume (ABV) - A measurement of the alcohol content of a solution in terms of the percentage volume of alcohol per volume. This measurement is always higher than Alcohol by Weight.
- Alcohol by Weight (ABW) - A measurement of the alcohol content of a solution in terms of the percentage weight of alcohol per volume. For example, 3.2 per cent alcohol by weight equals 3.2 grams of alcohol per 100 centilitres of beer. This measure is always lower than Alcohol by Volume.
Now that you're equipped with some of the must-know terminology, learn about the key aspects of ensuring your home distillation journey goes smoothly in our article Essentials for Home Distillation Success.
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