Brewer’s yeast has been engineered to produce two molecules that are partly responsible for the hoppy flavour in beer, reports a study published in Nature Communications. The findings could help to reduce the beer industry’s dependence on hop flowers and produce a consistent hoppy flavour in beer.

Hops are an expensive ingredient for breweries and a consistent hoppy taste relies on the stable content of essential oil in hop flowers. However, this can be affected by genetic, environmental, and processing factors.

Jay Keasling, Charles Denby and colleagues engineered brewer’s yeast to increase production of linalool and geraniol - two molecules found in essential oil, which have been identified as primary flavour determinants in hops. The authors did this by incorporating DNA from mint and basil into strains of brewer’s yeast and show that the engineered strain can give rise to the hoppy flavour in beer. In double-blind sensory taste tests involving 40 participants, the authors found that the engineered strain produced beer with a greater hoppy flavour than regular dry-hopped beer.

The authors note that although linalool and geraniol confer hop flavour to beer, the full flavour imparted by traditional hopping is likely to rely on a more diverse set of molecules.