In 2005, Joe Casey, a brewmaster at Widmer Brothers brewery in Portland, Oregon, faced sobering news for a man of his profession. His wife, Sara, was diagnosed with celiac disease, an allergic reaction to gluten that can cause dehydration, weight loss, and long-term immune disorders. This meant Sara could no longer enjoy her husband's award-winning (and gluten-rich) brew. "It sucked," says Casey, who soon devoted himself to brewing's final frontier – developing a good-tasting gluten-free beer.

On paper, Casey's quest seemed impossible – of all the things in the world to make gluten-free, beer may be the most challenging. Typically composed of barley, wheat, and rye, your average six-pack is a veritable soup of gluten. When established American breweries tried their hands at gluten-free brewing to take advantage of a growing $4.5 billion market, they replaced these ingredients with sorghum (a grass), rice, or raw sugar. It was akin to asking a winemaker to use peaches instead of grapes – the result tasted like someone had screwed up the recipe. "The challenge is to satisfy expectation," says Charlie Bamforth, a professor of brewing science at the University of California, Davis. "The gluten-free options just didn't taste like the beers most people wanted." Despite a market thirsty for good gluten-free beer, U.S. brewers couldn't crack the code. "Not much happening here except for sour bad taste," one reviewer recently stated about Dogfish Head's gluten-free Tweason'ale.

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Casey took a more scientific approach. While attending a brewer's conference in Seattle, he heard a lecture on a newly created enzyme, Brewers Clarex, that could break down the gluten protein in finished beer. Casey had hit pay dirt – he realized he could create beer with traditional malts and then eradicate the gluten before bottling, ensuring the familiar flavor survived. After two years honing his brew, he gave a growler to Widmer's celiac-suffering then CEO, Terry Michaelson, and brought a six-pack home for Sara. That night, Michaelson downed the growler in one sitting on his couch and Sara toasted her husband. "She was thrilled," Casey says. "It made her remember how badly she missed beer."

Casey's concoction was a triumph – he had made a gluten-free brew that tasted not only like beer but like really high-quality craft beer. Under the name Omission, Casey launched his first gluten-free beer, a lager, and soon afterward added a pale ale and an IPA. While Omission is a beer specifically created for celiacs, as many as 18 million Americans contend with milder gluten sensitivities – meaning Casey's creation may soon be changing happy hour's landscape. "For years, celiac sufferers have been told they can't have a barley beer that is gluten-free," he says, "and now we're making it."