Your Beer Actually Wants Flies In It
It turns out that yummy-beer-smell is the way the brewer’s yeast attracts fruit flies to facilitate dispersal, as yeast has neither wings nor legs and isn’t particularly good at going anywhere
except for my stomach. Beer scientist Bioengineer Kevin Verstrepen noticed that fruit flies would cluster around aromatic yeast and ignore non-aromatic yeast and so he decided to gather up his team of researchers at hte University of Leuven in Belguim and do some science.
Yeast produces compounds to mimic the scent of ripening fruit and scientists have already identified the gene responsible for the effect. Deactivating the gene eliminates the aroma while overactivating the gene produces a stronger aroma. Verstrepen’s study blew air into fruit fly cages collected from S. cerevisiae, or brewer’s yeast, cultures with different levels of fruity aroma.
Unsurprisingly the fruit flies were very attracted to the most pungent yeast while they did not notice the unscented yeast air. It was also observed that as the flies landed on the fruity yeast bits that their legs became a vehicle for hitchhiking microbes that were then able to travel around the inside of the cage. These findings were reported in the journal Cell Reports, though I’m curious to know if the research included observations of some bad fruit fly decision-making.
“Wild fermentation,” is a recent fad in beer-making where microbes are allowed to colonize a batch without intervention. Fruit flies could potentially be incorporated into this process to help select for the most aromatic yeast strains… the results of which could be delicious.