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 separated other 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: