Using the genetic diversity of beer yeast to create a completely new flavor of beer

Malt-based lager beer accounts for more than 90% of the world beer market. However, the variety of tastes, flavors, and aromas of lager beer is limited due to the limited number of commercially available yeast varieties available for production. In an attempt to create lager beer with a completely new flavor free from the constraints of commercially available yeast, hybridization experiments with newly discovered brewer's yeasts are being conducted.

Wild Patagonian yeast improve the evolutionary potential of novel interspecific hybrid strains for lager brewing | PLOS Genetics
https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1011154

We've unlocked exotic new beer flavors using genetics
https://theconversation.com/weve-unlocked-exotic-new-beer-flavors-using-genetics-237266

Beer made from malt is divided by the type of yeast used, with ales fermenting at around 15-20 degrees Celsius where the yeast floats to the surface at the end, and lagers fermenting slowly at a low temperature of around 10 degrees Celsius where the yeast sinks to the bottom at the end. In addition, there are many other types of beer depending on the fermentation temperature, type of yeast, and production method, and new styles of experimental craft beer are also becoming popular.

Lager is brewed using malt as the raw material and yeast that ferments disaccharides . Yeast is a single-celled fungus that ferments sugar into alcohol and carbon dioxide, and the traditional lager yeast is Saccharomyces pasteorianus . Saccharomyces pasteorianus has been optimized for brewing since it was domesticated hundreds of years ago, but the parent species, Saccharomyces eubayanus, had not been discovered in the wild until a few years ago, making it almost impossible to create a new lager beer.

However, in 2011, a wild species of Saccharomyces eubayanus was discovered on tree bark in Patagonia, Argentina. Since then, hundreds of strains have been discovered, and it has been found to have a surprising amount of genetic diversity.

Jennifer Molinet, a postdoctoral researcher in microbiology at Stockholm University, and her colleagues used the newly discovered genetic diversity of brewer's yeast to study hybrids that would broaden the range of flavors and aromas of lager. According to Molinet, three yeast strains found in southern Chile were particularly outstanding in that they were resistant to low temperatures, were effective at converting maltose into alcohol and carbon dioxide, and also had unique aromas.

In their research, Molinet and his team attempted to produce a new hybrid lager yeast by crossing Saccharomyces eubayanus with Saccharomyces cerevisiae, but initially they were unable to produce a strain with the desired characteristics, as it did not adapt well to fermentation conditions.

They attempted to find more desirable hybrids by cultivating the new hybrids for six months in a medium similar to beer wort to promote the natural evolution process and by extracting strains that showed superior fermentation ability and the ability to produce higher alcohol concentrations. As a result, the team reported that they had created an entirely new lager yeast that not only retained the strong fermentation characteristics required for commercial brewing, but also delivered new flavors never before smelled or tasted in lagers.

'We believe that this new hybrid yeast has the potential to revolutionize lager beer brewing, enabling craft brewers in particular to develop new and unique lager styles and set their products apart in a competitive market,' said Molinet. 'Furthermore, our research highlights the importance of biodiversity in brewing, and harnessing the natural genetic diversity of wild yeasts could play a key role in shaping the future of brewing to create innovative products.'