An international team of researchers has discovered that some of the most famous Belgian beers, considered as the most precious in the world, are fermented with a rare and unusual form of hybrid yeasts. These combine the DNA of traditional brewer's yeast (Saccharomyces cerevisiae) with wild yeast more resistant to stress (Saccharomyces kudriavzevii). A mixture that, according to experts argue, would be of medieval origin.
A new genetic study reveals that these hybrid yeasts used to make traditional Belgian beers combine features important of both parental species, such as the fermentation capacity of normal beer yeasts and stress tolerance and the ability to form special aromas of wildest ancient yeasts. "These yeasts are hybrids between two completely different species," explains Jan Steensels, from the VIB – KU Leuven Microbiology Center, who coordinated the laboratory work of this study, which is published this Monday in the journal 'Nature Ecology and Evolution'. "It's like we think of lions and tigers making a super baby," he jokes.
Scientists argue that this type of interspecific hybridizations are rare and appear to be favored by the domestication process. A new genetic analysis of these yeasts has shown how these specific hybrids originated in the Medieval germany and then they spread through different European breweries as the beers became more popular. "You could say that the unique habitat in the wooden fermentation barrels created by adventurous medieval Belgian brewers allowed these new species to thrive until today," argues Professor Kevin Verstrepen.
"In 2016, we reported that most industrial yeasts belong to or are of the Saccharomyces cerevisiae species, the traditional baker's and beer yeast," he explains. Brigida Gallone, also author of the study. "We now discover that these industrial yeasts are quite different from their wild progenitors, with different subfamilies that have adapted to beer, wine and bakery environments. We also noticed that some of the yeasts that were isolated from the old Belgian beer styles, like Gueuze and Trappist beers, they are even more unusual and they contain DNA from two different yeast species, "adds the researcher.
"Everything indicates that you are unique natural yeasts they allow the development of some of the most famous beers for which Belgium is so famous, "says Dr. Philippe Malcorps, principal scientist at the Global Center for Innovation and Technology at AB InBev, the world's largest brewer. The Malcorps team It helped with the isolation of yeasts from some of their spontaneous fermentation beer cellars.These natural super yeasts are living witnesses of brewing from pre-industrial times, adapted to the harsh fermentation conditions of the strong Trappist beers, or survival in the long beer typical of Gueuze beers.
"It is no accident that the origin of the current brewer's yeasts is found in Belgium and Germany, possibly the two countries most associated with the art of making this drink, "says Professor Mathias Hutzler of the University of Munich.
. (tagsToTranslate) Alcoholic beverages (t) Science