While the startup cofounders considered hoppy-tasting but hop-free beer potentially beneficial to brewers and the environment—as Denby said in a New York Times story after the paper was published—some hop farmers felt threatened. They feared engineered yeast could end a farming tradition and hollow out the soul of brewing, a dance of microorganisms, farmers, brewers, and hops stretching back to the 11th century.

Denby declines to talk on the record about the antagonism, which caught the company by surprise, but news of the provocative idea swept through the industry. “Early on, we had hop farmers calling us saying, ‘Crap, are you going to not use hops anymore?’” says Bryan Donaldson, brewing innovation manager at Lagunitas and a coauthor on the 2018 paper. (Some hop farmers are still on edge: “One guy stood up at a hop conference this year and said, ‘We don’t like these yeasts, because these yeasts can make hop flavors. This is the Beyond Meat of beer,” Jeremy Marshall, Lagunitas head brewmaster, recalls.)

Berkeley Yeast quickly pivoted. Denby and his cofounders interviewed more than 100 brewers to ask what the yeast strain of their dreams would do and found there wasn’t actually much interest in eliminating hops altogether, although some brewers wanted to reduce hop usage a little for cost reasons.

The feedback led Berkeley to focus on strains that improve efficiency, such as by removing diacetyl, or enhance natural hop flavors by adding specific compounds or enzymes. One example is the enzyme carbon-sulfur-lyase, which takes flavorless molecules present in malt and hops and frees flavorful components called thiols that in beer taste like tropical fruit. Berkeley created its Tropics strain by modifying a yeast commonly used for hazy IPAs to produce the enzyme.

Drinking Buddies

Since Berkeley Yeast evolved its pitch, many hop farmers have adjusted, too, realizing that new yeasts can make it easier for brewers to highlight nuanced hop flavors that could have otherwise been too difficult to isolate with a standard yeast. “I believe we could see an even bigger push toward hops that work with these new yeast strains,” says Brian Tennis, the founder of the Hop Alliance. “As hop growers, we need to make sure we are growing what the market demands.”

Although a fixture in craft brewing, to really hit the big time Berkeley Yeast will have to win over the largest multinational beer corporations such as Anheuser-Busch InBev and Heineken. Craft brewing makes up only one-quarter of the US beer market.

Major beer companies have been testing the startup’s yeasts, cofounder Denby says, although he declines to name them. Marshall, of Lagunitas—a craft beer powerhouse now owned by brewing giant Heineken—think’s it’s only a matter of time. “Somebody is going to jump in, and we are kind of standing on the precipice of that,” he says. “I don’t know who it’s going to be, but once they do I think it’s going to become commonplace.”

Lagunitas offers beers made with Berkeley strains in its taproom, including the Martial Martian Express that features “Uncanny Pineapple” flavors, but you won’t find any in grocery stores. Marshall says major beer distributors are still unsure whether consumers will be receptive to the concept of GMO yeast and would want to know whether GMO skepticism from the 1990s and early 2000s has dissipated.

Denby says he’s confident the biggest beer makers will eventually, like craft brewers, be unable to resist the creative potential and efficiency offered by engineered yeast. “It will take a longer time to scale, but the broader beer industry is going to change,” he says. Despite his original vision for the company, he’s also convinced that hops are here to stay, saying Berkeley’s goal is to complement the tradition, not threaten it.