Kevin Verstrepen, a yeast geneticist at the University of Leuven in Belgium, thinks that hundreds, even thousands, of new yeast strains that can be used to brew beer will come out of laboratories. Jeff Mello, who operates Bootleg Biology in Nashville, Tennessee, thinks they will come from backyards around the world.
They are both right. Verstrepen has served as a spokesman for a collaborative project to map the family tree of brewing yeast. “About half the team in my lab is now trying to make better beer yeast just by breeding. We’re playing catch-up with all the cow and pig farmers, looking for parents with the best genes to make high-quality offspring,” he says.
Mello is a local yeast evangelist. “If it takes shouting there is something in the air and it is unique, I’ll do it,” he says. He launched the Local Yeast Project in 2014 with a goal to collect wild yeast from every ZIP code in the country before he found out there are nearly 42,000 of them.
A wild yeast is generally defined as one not previously used in brewing, and such strains are found everywhere in nature. Only a very small percentage will ferment pleasant-tasting beer. Mello has collected about 200 cultures so far. “Our goal since the beginning is to expand the universe of yeast and bacteria available to brewers,” he says. “As more breweries start up mixed fermentation programs, they’re going to be looking for unique cultures to set themselves apart. Those cultures will often be from labs, but more and more, they’re going to be in the same air as the brewery.”
Using ZIP codes, he says, is an artificial construct, but it allows him to catalog differences from one region to the next. “It’s a way to think of yeast belonging to an area,” he says. “A character … it says only in Nashville would you get that wonderful strawberry flavor. Can I capture that in a city, in my backyard?” —Stan Hieronymus
Editor’s Note: This story is part of a special section on the future of beer, which appears in the March 2017 issue of All About Beer Magazine. This article contains sections on the future of water, malt, hops and yeast.