KU Leuven study uncovers hidden diversity in Scandinavian and Baltic farmhouse beer yeasts
A large-scale genetic study led by Kevin Verstrepen of Vlaams Instituut voor Biotechnologie (VIB) and KU Leuven, has identified a significant reservoir of beer yeast diversity in traditional farmhouse breweries across Scandinavia and the Baltic region, offering new potential for brewing innovation.
The research, conducted by the VIB-KU Leuven Centre for Microbiology and published in Current Biology, analysed 1,760 yeast samples from 44 farmhouse brewing cultures in Norway, Latvia, Lithuania and Russia.
Lost diversity preserved in farmhouse traditions
For centuries, brewing was a local and domestic activity, with yeast reused from one batch to the next in a process known as backslopping. This allowed yeast populations to evolve over time.
However, the introduction of single-strain starter cultures in the late 19th century, pioneered by Emil Christian Hansen at the Carlsberg brewery, led to more consistent production but also created a genetic bottleneck, with a limited number of strains dominating industrial brewing.
The new study shows that, in some remote regions, older and more diverse yeast cultures have survived. “We found a clear geographic structuring in farmhouse yeasts, indicating that local brewing traditions helped shape distinct regional lineages,” said Dr Jan Steensels of VIB and KU Leuven.
“The yeast genomes also revealed signs of admixture and strain exchange, especially between neighbouring brewers. Some Baltic strains even carried a unique horizontally transferred gene cluster, highlighting how these yeasts continued to evolve in ways rarely seen in standardised industrial settings.”
Potential for brewing innovation
Beyond their historical value, the researchers say these yeasts could play a role in the future of brewing.
“Many farmhouse yeasts retained a functional sexual cycle, a trait often lost in modern brewing yeasts," Verstrepen said, "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 flavour-producing potential, opening exciting possibilities for brewing innovation.”
The findings suggest that traditional brewing practices have preserved not only cultural heritage but also biologically valuable diversity.
Norwegian expert Lars Marius Garshol, who contributed to the study, said, “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.”
#FlandersNewsService | © PHOTO VIB
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