Brewers of barrel-aged sour beer take risks and practice patience. They wait as long as three years to see whether the cloudy liquids resting in oak ripen into shades of gold or raspberry and develop the ideal tart, tangy flavors or become undrinkable, ravaged by aggressive yeasts. It's an expensive gamble.
And even if they succeed, they may still have to persuade people to drink them.
“We still get customers who call to let us know a bottle of our barrel-aged beer had gone bad because it tasted sour,” said Vinnie Cilurzo, owner of Russian River Brewing Co. in Santa Rosa, Calif. “Sour beers will never become the pale ales of craft brewing.”
But for the brewers of sour beer, and its fans, the wait is worth it.
“I almost regret that we call them sour beers,” said Tom Nickel, owner of O'Brien's Pub in San Diego. “The word ‘sour' requires a bit of a leap of faith.” The best of some sour styles, such as gueuze, he said, have flavors like champagne or fresh lemonade. “You may not like the idea you're drinking sour beer, but your mouth will like it.”
Traditional sour beers are most popular in Belgium, home of lambics, gueuzes, and Flemish sour ales. But in the past few years American brewers have been trying their hand at imitating and riffing off those styles by fermenting with special yeasts and lactic acid bacteria.
Sometimes they age the beers in wood or stainless steel and add raspberries, cherries, apricots, and other fresh fruit for flavor, before blending the end results.
In 2002, when the Great American Beer Festival introduced its first sour categories, brewers entered just 15 sour beers. At last year's festival, brewers entered 119 sour beers in four categories: Belgian-style lambic or sour ale, American-style sour ale, German-style sour ale, and wood and barrel-aged sour beer.
Peter Bouckaert was one of the first brewers to produce sour ales in the United States. Bouckaert, a native of Belgium who had worked at breweries there, including Rodenbach, became brewmaster at New Belgium Brewing Co. in Fort Collins, Colo., in 1996. He released La Folie, a Flanders-style red, in 1999. It's one of the New Belgium's three wood-aged sour beers that are well regarded by aficionados, even though they make up less than 2 percent of its sales.
“Pushing in new directions is part of the true craft-brewing spirit,” Bouckaert said. “We're not going to do market research first.”
Allagash Brewing in Portland, Maine, produces sour beers using spontaneous fermentation, a traditional Belgian method of exposing the wort — beer before fermentation — to air, so it can come in contact with naturally occurring yeasts and bacteria. It's the first American brewery to do so.
“Some beer geeks are trying to catch me cheating,” said Jason Perkins, Allagash's brewmaster.
“If we wanted to add yeast to make a sour beer, we'd just do that. Instead we're trying to remain true to the traditional lambic style.
“The lambic brewers who inspired us have been doing these styles for hundreds of years, and they're still figuring it out,” Perkins said. “We still have a lot to learn.”