https://www.wired.com/story/the-secret-ingredient-in-your-craft-beer-gene-edited-yeast/
IT’S 2013 AND the craft beer boom is blooming across the United States. Eager young brewers are placing huge orders for new hop varieties that will soon make IPAs ubiquitous. Citra. Mosaic. Galaxy. Beer cans are churning off distribution lines, ale is flowing from taps, and money is gushing into breweries. But then some of the brewers who ignited the craze take home their cans. They find a glass in the freezer, pop the tab, pour a beautiful head of foam, take a sip—and gag.
Stomping all over those tropical fruit notes is the unwelcome taste of fake movie theater butter. “You’d take a sip and go ‘Wait a minute, that wasn’t there before,’” says J. C. Hill, the brewer and cofounder of Alvarado Street Brewery, a craft beer phenom from Monterey, California, that soared out of the 2010s boom. “I find it to make beer utterly undrinkable,” says Ryan Hammond, head brewer at Oakland’s Temescal Brewing a few hours’ drive north, which charted a similar path.
The odious culprit was a volatile compound called diacetyl, which has a distinctive buttery flavor once common on movie theater popcorn. About 10 years ago it began appearing unexpectedly in hop-heavy beers after they had been canned, turning balanced, fruity IPAs into buttery nastiness.
Brewers like Hill and Hammond can now look back on the diacetyl crisis with some nostalgia. The foul foe has been vanquished by a quieter revolution that has swept through craft beer over the past five years: genetically-modified yeast.
Alvarado and Temescal are both customers of Berkeley Yeast, a San Francisco biotech startup that has grown alongside craft breweries. It sells a “diacetyl-free” yeast with a tiny tweak to its genetic material that makes its cells produce an enzyme called ALDC. The enzyme prevents the diacetyl proliferation that brewers speculate can appear after canning when yeast hasn’t fully fermented some hop compounds. (For a GMO-free alternative, brewers can add off-the-shelf ALDC into brewing vats, but it makes the process more complicated).
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IT’S 2013 AND the craft beer boom is blooming across the United States. Eager young brewers are placing huge orders for new hop varieties that will soon make IPAs ubiquitous. Citra. Mosaic. Galaxy. Beer cans are churning off distribution lines, ale is flowing from taps, and money is gushing into breweries. But then some of the brewers who ignited the craze take home their cans. They find a glass in the freezer, pop the tab, pour a beautiful head of foam, take a sip—and gag.
Stomping all over those tropical fruit notes is the unwelcome taste of fake movie theater butter. “You’d take a sip and go ‘Wait a minute, that wasn’t there before,’” says J. C. Hill, the brewer and cofounder of Alvarado Street Brewery, a craft beer phenom from Monterey, California, that soared out of the 2010s boom. “I find it to make beer utterly undrinkable,” says Ryan Hammond, head brewer at Oakland’s Temescal Brewing a few hours’ drive north, which charted a similar path.
The odious culprit was a volatile compound called diacetyl, which has a distinctive buttery flavor once common on movie theater popcorn. About 10 years ago it began appearing unexpectedly in hop-heavy beers after they had been canned, turning balanced, fruity IPAs into buttery nastiness.
Brewers like Hill and Hammond can now look back on the diacetyl crisis with some nostalgia. The foul foe has been vanquished by a quieter revolution that has swept through craft beer over the past five years: genetically-modified yeast.
Alvarado and Temescal are both customers of Berkeley Yeast, a San Francisco biotech startup that has grown alongside craft breweries. It sells a “diacetyl-free” yeast with a tiny tweak to its genetic material that makes its cells produce an enzyme called ALDC. The enzyme prevents the diacetyl proliferation that brewers speculate can appear after canning when yeast hasn’t fully fermented some hop compounds. (For a GMO-free alternative, brewers can add off-the-shelf ALDC into brewing vats, but it makes the process more complicated).
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