The European Spirits Organisation

The Distillation Process

All spirits go through at least two procedures - fermentation and distillation. Fermentation is where all alcohol is created, distillation is where the alcohol is separated and removed. In order for fermentation to occur, two things are needed: A raw material in liquid form that contains sugar, followed by the addition of yeast. Yeast is a living organism that feeds on sugar; the bi-product of this consumption is alcohol and carbon dioxide (CO₂).

A simple formula for fermentation is:

YEAST + SUGAR = ALCOHOL + C0₂

Distilling is essentially the process whereby a liquid made of two or more parts is separated into smaller parts of desired purity by the addition and subtraction of heat from the mixture. The vapours/liquids distilled will be richer in content than any of their ingredients that have lower boiling points. Distilled spirits are produced from agricultural raw materials such as grapes, other fruit, sugar-cane, molasses, potatoes, cereals etc.

There are many subtleties involved in the creation of different spirits drinks but, by way of example, the process for a cereal-based spirits is as follows:

• Step 1: Milling. The raw material is ground into a coarse meal. The process breaks down the protective hull covering the raw material and frees starch.
• Step 2: Mashing. The starch is converted to sugar, which is mixed with pure water and cooked. This produces a mash.
• Step 3: Fermentation. The sugar is converted to alcohol and carbon dioxide by the addition of yeast. With the addition of yeast to the sugar, the yeast multiplies producing carbon dioxide which bubbles away and a mixture of alcohol, particles and congeners, or the elements which create flavour to each drink.
• Step 4: Distillation. The alcohol, grain particles, water and congeners are heated. The alcohol vaporises first, leaving the water, the grain particles and some of the congeners in the boiling vessel. The vaporised alcohol is then cooled or condensed, to form clear drops of distilled spirits.

Two additional steps are often taken in making some distilled spirits :

• Step 5: Ageing. Certain distilled spirits (e.g. rum, brandy, whisk(e)y) are matured in wooden casks where they gradually develop a distinctive taste, aroma and colour.
• Step 6: Blending. Some spirits go through a blending process whereby two or more spirits of the same category are combined. This process is distinctive from mixing since the blended spirit remains of the same specific category as its components.

Last updated on 16 January 2009.