Brewer's yeast is perhaps the most exciting ingredient in beer production, making beer a "living substance". Depending on the type of brewer's yeast, we usually distinguish between bottom-fermented (lager) and top-fermented (ale) beers. The biggest difference for the consumer is in the aroma of the beer. The main function of brewer's yeast is to produce alcohol and carbon dioxide from sugar, and it also forms the final flavor profile of the beer thanks to its secondary metabolism.
Bottom-fermented beers contain fewer, while top-fermented beers contain more yeast-derived secondary metabolites, aromas, and esters. An excellent example of this is the comparison of bottom-fermented Pécsi Premium Lager and top-fermented Pécsi Premium Wheat. While in the case of Premium Lager, the clean flavor profile derived from lager-type yeast merely supports the dominant aromas of malt and hops, the banana-like and clove-like flavors of Premium Wheat are due to the ale-type wheat beer yeast. Premium Wheat's special open-vat fermentation technology and its release in unfiltered form add to this, making the beer's flavor even richer.
