Beer — it’s not exactly healthy for you, but it’s been brewed for millennia, and it’s still one of the most popular beverages in the world. The world consumes around 190 billion liters of beer a year, and consumption is increasing yearly. But despite some diversification in the craft beer market, lager (the type of beer that’s fizzy, crisp and refreshing) is pretty limited in flavor and variation.

That may soon change thanks to a new batch of yeasts coming all the way from Patagonia.

The flavour of lager

Lager is a type of beer that is fermented and conditioned at low temperatures using bottom-fermenting yeast. This results in a clean and crisp type of brew, often with simple and rather bland flavors. This contrasts with ale, another primary beer category, which is fermented at warmer temperatures using top-fermenting yeast, leading to a broader range of flavors and aromas, often more robust and fruity.

Within these two broad categories, there are various substyles. Lagers include pilsners, bocks, and dunkels, while ales encompass styles like pale ales, stouts, and IPAs. But, for the most part, ale has the large flavor variety, and lager is the milder-flavored of the two.

Jennifer Molinet and Francisco Cubillos of the Universidad de Santiago de Chile believe they can change that.

Much of the flavor of lagers come from yeast, and there’s a lack of genetic diversity in the yeast used to brew them. Currently, there are only two types of this yeast, both resulting from the hybridization of common brewer’s yeast (Saccharomyces cerevisiae) and a wild, cold-tolerant strain (Saccharomyces eubayanus). But if other strains could be found, they could bring more varied flavor to lagers. This is exactly what Molinet and Cubillos are working on.

“The discovery of Saccharomyces eubayanus, the mother species of lager yeast, in the Argentinian Patagonia in 2011 was a significant breakthrough. This species, associated with native Nothofagus trees, has opened the door to creating novel lager yeast, which were previously limited in terms of genetic diversity,” says Cubillos.

“Since 2017, our research has been focused on identifying S. eubayanus strains across the Chilean Patagonia. This extensive collection of strains has allowed us to delve into the genetics of this species and trace the origin of the lager yeast mother. Our findings have provided a unique opportunity to recreate and generate novel lager strains, a possibility that was previously unattainable due to the lack of available S. eubayanus strains.”

Mixing wild yeasts

In the new study, the researchers created yeast hybrids using the strains from Patagonia. They grew the yeast at low temperatures and encouraged strains that had better fermentation qualities. These hybrids developed mutations that enhanced their ability to metabolize sugars like the ones used in beer fermentation. This, in turn, results in unique aroma profiles and a higher alcohol percentage.

All of this worked because of the great genetic diversity of the yeasts in Patagonia compared to other lineages. However, getting the yeasts to be suitable for a beer-specific context is still a challenge.

“Utilizing novel lager yeasts also necessitates adjusting current beer styles to enhance the yeast profile and optimize the interaction with hops and malts used in the brewing process. In our study, we used local strains for both parental species, carefully selecting for those exhibiting what’s needed in lager yeast: sugar consumption capacity, rapid fermentations at low temperatures and lovely aromas,” says Cubillos.

This research could revolutionize the lager industry by introducing a wider array of flavors and aromas. By harnessing the untapped genetic diversity of wild Patagonian yeasts, brewers can craft lagers with unique and complex profiles, similar to ales.

The potential to diversify the flavor spectrum of lagers not only enhances consumer choice but also supports sustainable brewing practices by utilizing naturally occurring yeast strains.

“We hope that novel lager yeasts will be considered to diversify the current repertoire of beers available worldwide. The more we survey, the more we can contribute in terms of biotechnological applications and knowledge about these processes. Our results also highlight the importance of bioprospecting efforts and the need to protect our local and natural resources. “

This innovation underscores the significance of preserving biodiversity and exploring biotechnological applications in food and beverage industries, Cubillos concludes.

“The Patagonian Forest is a reservoir of hidden genetic diversity, and we are committed to uncovering its potential. Our next steps include continuing to explore and characterize these yeasts to better understand their properties and applications in brewing.”

Journal Reference: Molinet J, Navarrete JP, Villarroel CA, Villarreal P, Sandoval FI, Nespolo RF, et al. (2024) Wild Patagonian yeast improve the evolutionary potential of novel interspecific hybrid strains for lager brewing. PLoS Genet 20(6): e1011154. https://doi.org/10.1371/journal.pgen.1011154