In a world dominated by malt and hops, sour beers stand alone.
Yet demand for the Belgian-style brews, known for their tart acidity, is growing.
Places like World of Beer are finding that some emerging craft-beer enthusiasts are looking for a new flavor beyond the ultra-hoppy IPAs, malty dopplebocks and everything in between.
Kenny Wright, product manager at the Brewery District spot, said sour beers have a public-relations problem. Sour indicates it's past its prime, cheap or spoiled.
"It's not an attractive word," he said.
But drinking sour beer is not like drinking lemonade, he said. The beers are amazingly complex, offering up bright acidity, funky yeast and a rustic woodsy flavor. Like other beers, some are more mellow and others more assertive.
"There's no mistaking a sour beer on the first sip," Wright said. "It's surprising. It's refreshing."
Brewing sour beers is complex, using wooden barrels -- usually oak -- in the fermentation process. It also involves a wild strain of yeast -- usually brettanomyces -- and bacteria, such as pediococcus or lactobacillus, which give the beer its pucker power.
Vinnie Cilurzo, owner of Russian River Brewing Co. in California, said microbreweries shy away from sour beers for many reasons, one being the unpredictability of the brewing process.
"The beer tells us when it's ready," he said.
Breweries worry about cross-contamination, which can ruin an entire operation. So, sour beer brewing requires separate pumps, filters, bottlers and other equipment. It also can take a year to make and many smaller breweries don't have the space to store barrels.
"It's a huge commitment on a big scale, but it's also a big commitment on a small scale," he said.
Russian River, which also has a brew pub, makes six sour beers, representing 10 percent of its total production. It's sold in draft and in bottles, with distribution limited mostly to California.
"It's become quite a big seller. It certainly didn't happen overnight," Cilurzo said, noting there was a learning curve for customers.
"It's easier to apply that in a brew pub setting because we can give them a taste off the tap," he said.
Donnie Austin, owner of House Wine in Worthington, says wine aficionados often find a compatible mate in sour beers.
"I think people who are interested in the complex and sophisticated characteristic of wine and cocktails are venturing toward the Belgian styles, and sour category overall," Austin said.
"I think there's an evolution of the wine drinker. I think people eventually move into higher acid wines," he said.
"And I think those wine drinkers are the folks who would be interested in sour beers. It's not just something you gulp back."
Magdiale Wolmark, chef and owner of Till Dynamic Fare in Victorian Village, said sour beers complement rich, gamy flavors, such as his duck liver pate and lamb burger with smoked goat cheese.
"I would say not every sour beer is a food-friendly beer," he said. "It's got to have the right balance. If it's too aggressive in one area, it's going to negate the general qualities of the beer."
Wolmark is serving the Monk's Cafe Flemish Sour, brewed in Belgian for Monk's Cafe in Philadelphia. When it's recommended, customers hesitate at first, he said.
"The people who taste it immediately fall in love with it," he said.
For the time being, he confines the style to the "beer geek" category.
"I think it's an experimental thing for people," he said.
Whether it becomes the next go-to beer is another story.
"I think things catch on if they're good," he said.