FERMENTED PASTS

FERMENTED PASTS is a DFF-funded research project exploring the hidden microbial history of traditional fermentation. Using ancient DNA, metagenomic sequencing, and microbiological methods, the project investigates historical brewing artefacts - including yeast rings, fermentation barrels, tools, and other residue-bearing objects - to recover traces of past yeasts and their associated microbial communities.

The project asks how local brewing traditions shaped microbial diversity over time, and how this diversity changed with industrialisation and the widespread adoption of standardized pure-culture brewing. A particular focus is Norwegian farmhouse brewing and kveik: traditional yeast cultures maintained through generations of rural brewing practice. By comparing historical material with modern fermentation cultures, FERMENTED PASTS investigates which microbial lineages and traits persisted, which may have been displaced or lost, and how mixed fermentation communities contributed to distinctive brewing practices.

The project also extends this work into the deeper past by investigating whether microbial DNA can be recovered from older archaeological materials associated with fermentation and drinking, including Viking and medieval drinking horns and archaeological pottery vessels. These materials may provide rare evidence of the microbial communities involved in early brewing and food fermentation traditions.

A central ambition of FERMENTED PASTS is to identify lost or overlooked microbial diversity with potential relevance beyond archaeology. Historical yeasts and associated microbes may carry useful functional traits—such as tolerance of high temperatures or alcohol, efficient fermentation, flocculation, resilience, or distinctive flavour profiles—that are underrepresented in modern industrial strains. Where possible, the project will seek to characterise and revive selected historic yeasts, creating opportunities to test their fermentation potential and explore how microbial heritage might inform more diverse, sustainable, and innovative brewing practices.

FERMENTED PASTS brings together archaeology, genomics, microbiology, and cultural heritage research at the University of Copenhagen, in collaboration with partners at the Norwegian University of Science and Technology (NTNU), the Norwegian Institute of Bioeconomy Research, the National Museum of Denmark, and the Carlsberg Research Laboratory. Together, the project aims to connect the past and future of fermentation: recovering microbial diversity shaped by centuries of brewing tradition while exploring its potential value for contemporary brewing and biotechnology.

Project period: 2025-2028

Principal Investigator

Dr. Hannes Schroeder Associate Professor Section for Molecular Ecology & Evolution Globe Institute E-mail: hschroeder@sund.ku.dk  Mobile: +45 42 52 36 14

Researchers