Stanford DNA study reveals evolution of beer yeasts

Lager lovers convinced that their beer of choice stands alone should prepare to drink their words this Oktoberfest. New research by geneticists at the Stanford University School of Medicine indicates that the brew, which accounts for the majority of commercial beer production worldwide, owes its existence to an unlikely pairing between two species of yeast—one of which has been used for thousands of years to make ale.

“These long-ago brewers were practicing genetics without even knowing it,” said geneticist Gavin Sherlock, PhD. “They’ve given us a very interesting opportunity to look at a relatively young, rapidly changing species, as well as some very good beer.” The research was published online Sept. 11 in Genome Research.

It all started with some unhappy Bavarians. Dissatisfied with the quality of beer brewed in the summer months, they forbade brewing the beverage when the weather was warm. However, colder winter temperatures inhibited fermentation by the ale yeast that had been used for hundreds of years and fostered an unlikely pairing with a second, heartier species—producing an unusual crisp, clear brew that became today’s lager.