A GENETICALLY engineered yeast makes beer taste of hops – without any actual hops. The yeast could help make brewing beer cheaper and more sustainable.
Hops are the flowers of the hop plant . They give floral and bitter flavours to beer, but their high cost contributes to the price tag of craft beers. What’s more, growing hops uses lots of water and energy, and the amount of flavour they impart varies.
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So , and colleagues at the University of California, Berkeley, set out to create a yeast that produces some of the chemicals responsible for the flavour of hops. They focused on two, linalool and geraniol, that are known to be crucial to the flavour.
Mint and basil plants have enzymes that make these chemicals, so the team found and then inserted the genes responsible into yeast. The resulting strains of yeast made beer with more consistent levels of linalool and geraniol than beer made with hops.
Because I’m hoppy
A tasting panel said the beer was hoppier than two beers flavoured with real hops, and reported pleasant flavours like orange blossom. “We were hoping to be on the same range as the dry-hopped beers,” says Denby. “Being rated as hoppier was very encouraging.”
Denby says it takes 50 litres of water to grow enough hops to make one pint of beer, so cutting back on their use could lessen our overuse of water.
What’s more, Li wants to go further and use engineered yeast to create entirely new flavours. “We think that using hops for brewing has just scratched the surface of what flavours can be made by varying combinations and concentrations of hop flavour molecules,” she says.
However, hops contribute hundreds of aroma compounds, so it will be difficult for synthetic biology to mimic the complex flavours they create, says at the University of Leuven, Belgium. “Of course, that does not mean that this new technology is not interesting, especially to help tune beer flavour and perhaps produce novel beers with aromas that would be hard or impossible to reach through classic brewing.”
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Nature Communications
