New technology could enable your favorite India Pale Ale or American Amber Ale to be as hoppy as ever—without being brewed with actual hops.
Biologists from the University of California Berkeley have developed a way to create the flavors and aromas of hoppy beers without hops, by producing strains of brewer’s yeast with the gene editing technology CRISPR-Cas9 that both ferments the beer and provides two of the prominent flavor notes provided by hops.
To achieve this, the researchers inserted four new genes, as well as the promoters that regulate the genes, into industrial brewer’s yeast using the gene editing tools. Linalool synthase and geraniol synthase—two of the genes used that came from mint and basil—code for enzymes that produce flavor components common to several plants.
Genes from other plants that were reported to have linalool synthase activity—including olive and strawberry—were more challenging to work with.
Two other genes from yeast boosted the production of precursor molecules required to make linalool and geraniol—the hoppy flavor components.
All the genetic components—the Cas9 gene, four yeast, mint and basil genes and promoters—were inserted into yeast on a tiny circular DNA plasmid. The researchers used the yeast cells to transplant the Cas9 gene into the Cas9 proteins, which cut the yeast DNA at specific points. Yeast repair enzymes were then spliced in the four genes and promoters.
Brewers need at least 50 pints of water to grow the hops needed for each pint of beer. They also need fertilizer and energy to transport the crop, making cultivating hops for beer an expensive process.
Hops’ flavorful components, or essential oils, are also highly variable from year to year and plot to plot, meaning a standardized yeast could yield a uniformity of flavor.
This process could be avoided by using yeast to make a hop-forward 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,” Charles Denby, a former UC Berkeley postdoctoral fellow, said in a statement.
To test this, the researchers asked Charles Bamforth, a malting and brewing authority at UC Davis, to brew a beer from three of the most promising strains, using hops only in the initial stage of the brewing.
They then presented the lab-created beer and a control version of the beer that was made using traditional processes to 27 employees of Lagunitas Brewing Company. In double-blind taste tests, the tasters said the beer made from engineered strains was more hoppy than the control beer.
Denby started Berkeley Brewing Science with the aim to market hoppy yeasts to brewers, including strains that contain more of the natural hop flavor components. They also hope to create other strains that incorporate novel plant flavors not usually in beer from the canonical ingredients of water, barley, hops and yeast.
Filed Under: Genomics/Proteomics
