The impact of commercially available ale and lager yeasts strains on the fermentative diversity of beers

Yeasts from the species Saccharomyces cerevisiae (ale yeast) and Saccharomyces pastorianus (lager yeast) are the main component of beer fermentation. It is known that different beer categories depends on the use of specific ale or lager strains, where the yeast will imprint its distinctive fermentative profile to the beer. Despite this, there is no studies reporting about how diverse, rich, and homogeneous are beer categories in terms of commercially available brewing yeast strains. In this work, the diversity, richness, and evenness of different beer categories and commercial yeast strains available for brewing were evaluated by applying quantitative concepts of ecology analysis in a sample of 121,528 beer recipes. For this purpose, the frequency of ale or lager and dry or liquid yeast formulations usage was accessed and its influence in the fermentation temperature, attenuation profile, and number of recipes for a beer category were analyzed. The results indicated that many beer categories are preferentially fermented with dry yeast strains formulations instead of liquid yeasts, even considering the high number of available liquid yeast formulations. Moreover, ale dry strains are preferentially used for lager brewing. The preferential use of specific yeast formulations drives the diversity, richness and evenness of a beer category, showing that many yeast strains are potentially and industrially underexplored.