Could the future of brewing be found in a remote Scandinavian farmhouse?

For thousands of years, brewing was a domestic and local practice. Homebrewers typically reused yeast from one batch to the next in a process known as backslopping, allowing yeast populations to evolve over generations under changing environmental conditions. ​

That changed dramatically in the late 19th century, when brewers began using pure single-strain starter cultures and frozen stock preservation. While these innovations improved consistency and control, they also created a major genetic bottleneck: only a small number of strains came to dominate industrial brewing, and much of beer yeast biodiversity disappeared.

Hidden diversity

A new collaborative study led by Prof. Kevin Verstrepen of the VIB-KU Leuven Center for Microbiology shows that in a number of remote farmhouse brewing traditions, that lost diversity has endured. With the help of Norwegian expert Lars Marius Garshol, the team collected 1,760 yeast isolates from 44 farmhouse ale cultures across Norway, Latvia, Lithuania, and Russia. In these long-maintained brewing cultures, they encountered an extraordinary range of Saccharomyces cerevisiae beer yeast strains. Some cultures were close to monocultures, while others contained complex communities with more than 30 distinct yeast variants.

“We found a clear geographic structuring in farmhouse yeasts, indicating that local brewing traditions helped shape distinct regional lineages,” explains Dr. Jan Steensels, postdoctoral researcher in the Verstrepen lab. “The yeast genomes also revealed signs of admixture and strain exchange, especially between neighboring brewers. Some Baltic strains even carried a unique horizontally transferred gene cluster, highlighting how these yeasts continued to evolve in ways rarely seen in standardized industrial settings.”

The results suggest that traditional farmhouse yeasts may offer a rare glimpse into the kinds of diverse brewing cultures that once existed widely across medieval Europe before industrial standardization narrowed the field.

A resource for future brewing

But beyond their historical importance, these yeasts could prove highly valuable for the future, as brewers seek new flavors, improved resilience, and more sustainable fermentation processes.

“Many farmhouse yeasts," explains Verstrepen, "retained a functional sexual cycle, a trait often lost in modern brewing yeasts. They also show broader tolerance to temperature and other stresses, consistent with the demanding and variable conditions of farmhouse brewing. In addition, many strains displayed more diverse flavor-producing potential, opening exciting possibilities for brewing innovation.”

The study highlights how traditional brewing methods have preserved not only cultural heritage, but also biological diversity with real scientific and industrial value.

Garshol: “Our findings show that the next innovations in beer may emerge not only from new technologies, but perhaps even more importantly, from the survival of some of its oldest practices.”

Publication

Distinctive domestication of farmhouse beer yeasts preserved pre-industrial genetic and phenotypic diversity. Bircham, et al. Current Biology, 2026. DOI: 10.1016/j.cub.2026.03.030

Funding

This research was funded by VIB, KU Leuven, VLAIO, the Research Foundation – Flanders the (FWO), European Research Council (ERC), and HORIZON-MSCA.

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