Gene-edited yeast dominates craft beer.

Gene-edited yeast dominates craft beer.

Genetically-Modified Yeast Revolutionizes Craft Beer Industry

Craft Beer Boom

It was the year 2013, and the craft beer phenomenon was sweeping across the United States. With eager young brewers placing massive orders for new hop varieties, the popularity of IPAs was skyrocketing. Citra, Mosaic, and Galaxy hops were becoming ubiquitous, and breweries were thriving. However, some brewers experienced a rude awakening when they opened their cans – a putrid taste of fake butter reminiscent of movie theater popcorn. This unwelcome flavor was caused by diacetyl, a volatile compound that infiltrated hop-heavy beers after canning, turning once fruity IPAs into undrinkable brews.

Craft breweries like Alvarado Street Brewery and Temescal Brewing were particularly affected by this diacetyl crisis. They experienced first-hand how this nasty compound ruined their meticulously crafted beers. Fast forward to today, and brewers like J.C. Hill from Alvarado Street Brewery and Ryan Hammond from Temescal Brewing can reminisce about the diacetyl crisis with nostalgia. Thanks to a quiet revolution that has swept through the craft beer industry, genetically-modified yeast has emerged as a savior.

Berkeley Yeast

Berkeley Yeast, a biotech startup based in San Francisco, now offers craft brewers a “diacetyl-free” yeast. This genetically-modified yeast has a minor tweak to its genetic material, causing it to produce an enzyme called ALDC. This remarkable enzyme prevents the proliferation of diacetyl, solving the problem of buttery off-flavors once and for all. Brewers can choose to use Berkeley Yeast’s genetically-modified yeast directly or, for a GMO-free alternative, add off-the-shelf ALDC into their fermentation process. Either way, the result is a clean and crisp beer that is free from the diacetyl curse.

However, Berkeley Yeast doesn’t stop at diacetyl-free yeast. The company offers a wide selection of designer yeasts that cater to craft brewers’ diverse needs. One popular strain called Tropics produces an enzyme that injects guava and passionfruit overtones into the beer. This strain is responsible for the tropical explosion found in Temescal’s Secret Solutions Double IPA and Bee Gee IPA from Watts Brewing Company in Bothell, Washington. Another strain, Sunburst, adds delightful pineapple flavors, while Galactic produces lactic acid for sour beers without the need for the lengthy traditional brewing process. Berkeley Yeast has even conducted experiments suggesting that engineered yeast can produce hoppy beer without hops at all, although this idea remains controversial.

The impact of Berkeley Yeast’s genetically-modified yeast strains on the brewing industry cannot be understated. Craft brewers all across the United States have enthusiastically adopted these strains, with many exclusively using Berkeley Yeast for all their beers. While Berkeley Yeast declines to share specific numbers, several craft brewers have confirmed that their industry peers are either already using or considering Berkeley Yeast’s strains. In marketing and labeling, brewers often credit the company’s yeast, particularly when it is used for flavor improvements.

“The diacetyl-free Chico yeast from Berkeley – that’s pretty much exclusively what we use in-house for our beers,” says Tim Sciascia, head brewer at Cellarmaker Brewing, a highly regarded San Francisco brewery. “The crew at Berkeley is messing around at a level that’s just so far beyond what anyone else is doing.”

While Berkeley Yeast’s genetically-modified yeast strains have garnered praise within the craft beer community, they have also faced criticism. Traditional beer purists and hop farmers have voiced concerns, seeing the startup as a threat to the longstanding traditions of brewing and hop farming. The antagonism caught Berkeley Yeast by surprise, as they never intended to eliminate hops entirely. Cofounder Charles Denby conceived the idea from his passion for home brewing and a desire to reduce the resource-intensive aspect of brewing, like hops.

Denby and his team quickly pivoted in response to feedback from brewers. They discovered that the brewing community was not interested in completely eliminating hops but rather in enhancing efficiency and highlighting specific hop flavors. By improving the natural hop flavors and removing undesirable compounds, Berkeley Yeast’s strains provided brewers with the “hop strain of their dreams.”

Hop Field

This shift in focus has prompted a change of heart among hop farmers as well. Rather than seeing genetically-modified yeast as a threat, they now recognize the value it brings to brewers. These new yeasts allow brewers to showcase nuanced hop flavors that could be difficult to achieve with traditional yeast strains. Brian Tennis, founder of the Hop Alliance, believes that the industry will witness a significant push towards hops that work well with these innovative yeast strains.

Berkeley Yeast’s success in the craft beer industry hinges on persuading multinational beer corporations, like Anheuser-Busch InBev and Heineken, to adopt their genetically-modified yeast. While craft brewing constitutes only a quarter of the US beer market, major beer companies have already begun testing Berkeley Yeast’s strains. Lagunitas, a craft beer powerhouse owned by Heineken, currently offers beers made with Berkeley strains in its taproom. However, widespread adoption requires the buy-in of major beer distributors and the acceptance of consumers, who may still harbor skepticism towards GMO products. Despite this challenge, Denby remains confident that the broader beer industry will change and embrace the creative potential and efficiency offered by engineered yeast. He also affirms that the vision of Berkeley Yeast is to complement the brewing tradition, demonstrating that hops are here to stay and their goal is to enhance the art of brewing rather than replace it.

The introduction of genetically-modified yeast strains from Berkeley Yeast has revolutionized the craft beer industry and provided brewers with exciting new possibilities. From eliminating off-flavors to enhancing hop characteristics, these strains have become an indispensable tool for craft brewers across the country. As the industry continues to evolve, it will be fascinating to see how the use of genetically-modified yeast shapes the future of brewing, highlighting the ingenuity and creativity of brewers and the dynamic nature of the craft beer landscape.