The fungi present in beer belong to the genus Saccharomyces, which is a type of yeast. Yeasts are a type of fungi that play a crucial role in the fermentation process of beer production. The specific strain of yeast used in brewing is Saccharomyces cerevisiae, commonly known as ale yeast, for top fermentation, and Saccharomyces carlsbergensis, known as lager yeast, for bottom fermentation.
When it comes to brewing, it is customary to refer to the ale yeasts as top strains of Saccharomyces cerevisiae. These yeasts are responsible for the fermentation process that takes place at warmer temperatures, typically between 15-24 degrees Celsius (59-75 degrees Fahrenheit). The top strains of S. cerevisiae are known for producing ales, which are generally characterized by their fruity and complex flavors.
On the other hand, lager yeasts are referred to as bottom strains of Saccharomyces carlsbergensis. These yeasts are used in the fermentation process that occurs at lower temperatures, usually between 7-13 degrees Celsius (45-55 degrees Fahrenheit). The bottom strains of S. carlsbergensis are responsible for producing lagers, which are known for their crisp and clean taste.
In my experience as a brewer, working with these different strains of yeast has been fascinating. Each strain brings its own unique characteristics and flavors to the beer, ultimately contributing to the diverse range of styles and tastes that we enjoy.
It is important to note that while Saccharomyces cerevisiae and Saccharomyces carlsbergensis are the most commonly used yeasts in brewing, there are other yeast strains and even bacteria that can also play a role in the fermentation process. For example, Brettanomyces is a type of yeast that is often associated with sour beers and can contribute to their distinct tartness.
The fungi present in beer are yeasts, specifically strains of Saccharomyces cerevisiae for ales and Saccharomyces carlsbergensis for lagers. These yeasts are responsible for the fermentation process that gives beer its alcohol content and unique flavors.