The microbe that has a major role to play in the process of beer fermentation is called yeast.

Yeasts are eukaryotic, unicellular organisms, and are technically members of the fungi kingdom.

The role of yeast is to metabolize the sugars that are present in the barley grains. This metabolization process results in the formation of carbon dioxide and ethyl alcohol, which then turns wort into beer. The types of yeast used in beer making are ale yeast and lager yeast.

Some of the specialized yeast strains that are used to produce world-famous beer varieties such as Budweiser, Corona, Carlsberg, etc., are actually trademarked. They are a closely guarded industry secret, and more information about these strains is very difficult to find.

The Hallertau strain of yeast, used by the Budweiser Company, is trademarked by them.

Thus, these special varieties of yeast aren’t easily available everywhere. Most of the research in this area is done in Germany and Austria, which are home to some of the best beer brands in the world.

Most breweries and beer brands decide to develop a special kind of yeast for their product, and apply for patents and trademarks.

These strains of yeast are all patented/trademarked in the breweries’ home countries.