One Belgian laboratory's Friday evening beer fest has ended with a paper describing how to inject flavor into lagers by encouraging some sexual action between yeasts. Kevin Verstrepen, Stijn Mertens and collaborators at VIB laboratory for Systems Biology in Leuven showed with genetic studies that most lager fermentation results from a hybrid species of two parent yeasts—Saccharomyces cerevisiae, and S. eubayanus. Because these two species are so different, crossing them to make more diverse lagers has been unsuccessful. At least, so far. The researchers describe how they optimized growing conditions to foster mating between the two yeasts, which resulted in hundreds of new lager strains (Appl. Environ. Microbiol., doi:10.1128/AEM.02464-15, 25 September 2015). Of the 31 they tested in small-scale beer fermentors, only 10 performed well in terms of fermentation speed and flavor. Two, in particular, fermented even faster and produced novel aroma profiles compared with commercially available lager yeasts.

Credit: CHROMORANGE / Tscherwitschke / Alamy Stock Photo