Whisky is alcohol distilled from fermented grain and then stored in wooden barrels to mature. The grain varies from wheat, rye barley to corn. Different variations are Irish whisky, Scotch whisky and American whisky. Bourbon is the most popular type of American whisky.

Bourbon is whisky that is produced in a specific, precisely defined way. It must be produced in America and consist of 51% corn. While other types of whisky can be stored in oak barrels of any kind, bourbon must be stored in new, charred oak barrels. In addition, bourbon must be distilled to 160 proof and filled into the barrels at 125 proof*. All other whisky must be distilled to no more than 190 proof.

The liquid must be bottled and stored for at least 4 years in accordance with the guidelines under U.S. supervision.

When bottling, the liquid must not be less than 80 proof. It goes without saying that authentic bourbon must not contain any colourings, flavour enhancers or other additives. 

*Proof is a unit of measurement for the alcohol content in a liquid. 100 proof corresponds to 57.15 % Alc./vol (volume per cent).