Wine Is Made by a Bunch of Slutty Yeast

If you're drinking wine this evening, you might want to know that you owe your glass to a bunch of super sex-crazed strains of yeast who will hook up with just about anything they come across during the fermentation process. Cheers!

Researchers from Stanford University School of Medicine found that many commercial yeast strains are totally promiscuous, which makes their lineage difficult to trace, but it's also part of what makes wine so tasty. Gavin Sherlock, an associate professor of genetics and senior author of the research says,

The strain of yeast used in fermentation definitely affects the flavor of the wine, and we thought that these strains would fall into a nice evolutionary-tree-like structure with a common ancestor.

But that's not what happened at all. The yeast, which typically reproduces asexually, had gone slutty and was partnering multiple times with each other and even with members of different yeast species. Wow, sounds like a wild 70s key party in a wine barrel.

Researchers aren't sure whether the yeast's sluttiness was encouraged by winemakers and bakers over time, or whether it developed naturally, but it surprised them because it's not how yeast usually conducts its sexy business:

[M]ost yeast, at least during industrial processes, reproduce primarily by asexual budding - pinching off one identical daughter cell after first duplicating the parent's genetic material. Occasionally they go through sexual reproduction and form spores that can mate with another spore of the same species and then continue to bud asexually.

Kinky. But because of this they assumed that most of the yeast strains they looked at would have fairly pure lineages. Instead they found that it was all mixed up, with bits of DNA from various strains and species intermingled. Now that they've identified this interesting pattern of mating, Sherlock and his fellow researchers plan to investigate further and try to trace the genealogy of some of the strains in hopes of understanding how it affects wine production. As Sherlock says,

Historically, winemakers were just happy to see that fermentation was taking place. But it seems that all the sloshing about that occurs during the process may have facilitated some very interesting couplings.

Funny, since the same thing could be said about what happens after you spend an evening sloshing wine down your throat.

In vino veritas: Promiscuous yeast hook up in wine-making vats, Stanford study shows [EurekAlert]

Image via Steve Cukrov/Shutterstock.