UC Berkeley scientists are making leaps and bounds toward a more sustainable approach to brewing beer with the creation of a genetically engineered beer without hops, the main ingredient that gives beer its rich flavor.
The new beer mimics the flavors of hoppy beer. Hops — the flowers of the Humulus lupulus plant — are added during the beer brewing process to create different types of flavors, according to study co-author and former UC Berkeley postdoctoral fellow Charles Denby.
Denby and study co-author Rachel Li, a doctoral candidate in the Keasling Lab at UC Berkeley, started by creating a genetically modified brewing yeast cell that included genes from mint and basil plants. The genes were then made into enzymes that recreated the taste of hoppy beer.
“If (hops) are added at the initial stages of the brewing process, they add bitter flavors; if they are added at later stages of the brewing process, they add fruit and floral flavors,” Denby said.
Although the study began as a side project for Denby and Li, it became the subject of Li’s doctoral work as it gained momentum. The strain of yeast DNA took a couple of months to create, and the genetically engineered beer was created in about two weeks at UC Davis, according to Li.
Once the strain of genetically modified beer was created, Denby and Li took their work to Bryan Donaldson, the brewing innovation manager at Lagunitas Brewing Company, to conduct a blind taste test of the traditional hoppy beer with the genetically engineered beer. According to Li and Denby, participants in the taste test said they found the hopless beer’s flavors to be more desirable.
“We received positive feedback on the flavor profile of our beer, and (Donaldson’s) analysis was that our beer had desirable flavors, including ‘fruit loops and orange blossom’ and no undesirable or ‘off-flavors,’ ” Denby said.
UC Davis professor of malting and brewing sciences Charles Bamforth said it is unclear how the introduction of the engineered beer may change the market because most brewers are “traditionalists” and will continue to use their preferred yeast. He speculated, however, that breweries could save money on hops using this new discovery.
According to Li, genetically modified yeast can also provide a more sustainable alternative to the current brewing process.
It takes about 50 pints of water to grow enough hops for one pint of beer. Using standardized yeast instead of hops would also provide a uniformity to the flavor of the beers, as the essential oils that give hops their flavors vary from year to year and season to season.
“Growing hops requires a lot of natural resources: water for irrigation and energy for processing, transporting and storing/refrigerating,” Li said in an email. “By using these yeast strains, hoppy beers can be produced more sustainably than they currently are.”