Researchers in Ireland have now analyzed the microbial populations in Kefir, and using data collected over a 24-hour fermentation period, have been able to match individual microbial species with associated flavor compounds.
By tracking specific changes the microorganisms underwent during fermentation they were able to relate them to specific expressions of flavor, though the exact mechanism still remains a mystery.
One notorious microbe however, known as Acetobacter pasteurianus, has now been confirmed to be associated with an unnamed acidic, vinegary flavor. Another, called Lb. kefiranofaciens was correlated with a slightly cheesy after taste. Other microbial species were matched up with the associated metabolites* responsible for buttery and fruity flavors.
The study shows that a deeper understanding of microbial behavior during fermentation would be of great interest to researchers who believe that with just a slight tweaking of the microbial mix they could boost the health and taste benefits of various fermented beverages.
By studying Kefir the researchers also nurture a more robust model for their future understanding of other microbial communities where multiple bacterial species cohabitate in intriguing ways, such as in the gut or soil. Kefir provides researchers and ideal laboratory as the 24 hour fermentation period is relatively brief and the microbial mix relatively sparse compared to other fermented products such as sourdough bread, and various alcoholic beverages which can also be studied in a similar manner.
*A suspicious group of molecules.