ACHTUNG - Archivseite! Besuchen Sie uns auf unserer neuen Webseite www.Whisky.de

Bourbon - Yeast Management

Each distillery in Kentucky and Tennessee has its own yeast stock, which outlasted the Prohibition in cooled rooms. The yeasts are guarded so much as a secret that the companies have applied for patents for their isolated yeasts tribes. In contrast to Germany patents are possible in the USA for yeasts.

Four Roses - Refrigerator for Yeast Stocks

The selection of the yeast took place in a simple manner. Containers with a nutrient solution were placed under an apple or pear tree. One waited until natural yeasts on the fruits also accepted the nutrient solution. Then small samples of the nutrient solution were put on carriers and the individually upshowing yeasts were bred in ovens and kept at moderate temperatures (35 to 40°C). From one single yeast cell you can breed the entire yeast for the alcoholic fermentation.

From a test tube the yeast amount as much as a pencil tip, is taken out. This yeast is mixed in a glass bulb with a nutrient solution (Malt extract). Important for the reproduction of the yeast is the correct pH value of the solution. Depending upon the yeast it varies between 5,4 and 5,8.

Early Times - Yeast Tribes

All materials in which the yeasts are bred, must be sterilized before in a autoclave, so that not vinegar bacteria or different yeasts replace the desired yeast tribe.

Early Times - Autoclave

After about half a litre of pure yeast has been produced in this glass bulb, the yeast is added into a larger container the so-called 'Dona Tub' (Donna Tub).

Early Times - Dona Tub

A large yeast batch is produced in the Dona that a large container can be filled later which serves as a storage tank for the entire fermenters.

Early Times - Yeast Tanks

Early Times - Yeast tank from the inside (before reproduction)

Early Times - Yeast tank from the inside (strong reproduction)

Each distillery usually produces different Bourbons with different yeasts. Therefore each whiskey has its own yeast tank. The reproduction of the yeasts over the Dona therefore takes place occasionally, if the yeast stocks were spoiled by vinegar bacteria or alien yeasts.

Fermentation - Back to Start