Few things are more distinctive than the bitter zest of a hoppy beer. Hops, the flower of of the plant Humulus lupulus, has been used to give hoppy beers that characteristic flavor for centuries. But hops are expensive and require lots of water to grow. So scientists figured out how to do without. As Douglas Quenqua reports for The New York Times, Charles Denby, a biochemist at the University of California, Berkeley, and his colleagues have created a beer that tastes and smells hoppy — sans hops.
Denby works in a lab that uses plant molecules called terpenes to create sustainable fuel. But he is also a home brewer, Quenqua writes. When Denby learned that some terpenes could mimic the taste of hops, he decided to experiment.
The goal was to craft a brew with the flavor of Cascade hops, a popular variety used in many craft ales and India Pale Ales (IPAs). So the researchers first isolated the various oils naturally produced by hops, writes Quartz’s Katherine Ellen Foley. Once they found other plants that naturally produce the same oils, they isolated the genes that created the distinctive zest. After several trials, they found that genes from mint and basil worked best.
The team genetically modified strands of DNA from brewer's yeast, an essential ingredient in beer that converts sugar to alcohol, inserting series of DNA from the basil and mint. This allowed the yeast to produce the hoppy oils. They detailed their experiment in an article published this week in the journal Nature Communications.
As Katie Langin reports for Science, the team then brewed up some beer using their modified yeast. And the results were convincing. Taste testers gave the scientists’ creation a “hoppier” rating than a traditionally hopped beer in a blind taste test. "This was one of our very first sensory tests, so being rated as hoppier than the two beers that were actually dry-hopped at conventional hopping rates was very encouraging," Rachel Li, a UC Berkeley doctoral candidate and co-author of the study, says in a UC Berkeley press release.
Though hops have been used in beer for centuries, it’s still a comparatively new ingredient in the long timeline of the fizzy drink. As Philly Beer Scene reported in 2010, beer has been produced for thousands of years. But it wasn't until the 8th century when records of hops started to appear.
Its popularity has risen over the years, with some brewers considering hops as essential as water or barley in the brewing process. German beer purity law even dictates that beer be made out from water, hops, barley and yeast, according to the Hop Growers of America. The popularity of American IPAs has also sparked a trend of brewers developing beer so hoppy it reaches max bitterness levels. Added for flavor and aroma, hops were originally used as a preservative, helping the brew last longer.
But hops are expensive and unsustainable, according to the university press release. In fact, 50 pints of water are used just to grow the hops required to make one pint of craft beer. Denby hopes his research can help brewers use yeast to make hoppy beer. "My hope is that if we can use the technology to make great beer that is produced with a more sustainable process, people will embrace that," Denby says in the statement.
With that in mind, Denby and Li have launched a startup called Berkeley Brewing Science, and they plan to market several strains of hoppy yeasts for brewers.