It’s fun to watch uninitiated beer drinkers sample sour beer for the first time. Even if they’re well aware of the oncoming pinch of acidic tartness, they inevitably grimace and recoil. After a few more sips, however, their tongues adjust to the physical sensation and their palates warm up to the complexity of flavor.

I witnessed this phenomenon at last year’s first annual Brewvival beer festival in North Charleston. The fest organizers from COAST Brewing Co. and the Charleston Beer Exchange made a point to arrange tastes of rare, hard-to-find specialty ales from small domestic breweries. I couldn’t help but laugh as I watched small packs of attendees circle around some of the booths, wincing and squinting with every sip of New Belgium’s super-tart NBB Love or the dark and fruity Duck-Rabbit Cherry Madness — two of a growing number of new beers inspired by the sour classics.

“These beers are limited and hard to come by,” says Scott Shor of the Charleston Beer Exchange, a professed sour head. “As big sour beer fans, we make a concerted effort to order and stock as many sour beers as we can come by. When you compare the number of sour beers in our store versus other categories, it’s rather miniscule. But there’s an uptick in popularity right now.”

Flanders reds, lambics, gueuzes, saisons, oude bruin, and Berliner weisse are classic styles that have been around for years — brewed mostly in Belgium, Germany, and France. Most are aged for years in wood, bottle-conditioned, and cellared.

Their acidic sourness comes from a source of fermentation that would be considered a defect in other lagers and ales. Wild yeast strains like Brettanomyces (a component of lambic beer) or bacteria like Lactobacillus (as used in the wheat beers of Berlin) normally wreak havoc in standard brewhouses, but makers of sour beers embrace their unusual qualities. The Brettanomyces yeast adds distinct aromas and flavors, some of which can seem quite earthy (imagine the whiff of a damp barnyard) or downright funky. The bacteria create strong sour notes and acidity.

As a niche, sours are not for everyone, particularly beer novices who prefer light lagers.

“I didn’t always like sours,” admits Shor. “There’s a whole thing about it being an acquired taste — something you have to expose yourself to and open your mind to and gradually appreciate. I think there’s more art behind making a good sour beer, which is so, so hard to do.”

While some of the most intense commercial examples of sour beer could twist the faces of even the most enthusiastic sourpusses, some are a bit more mellow and fruity.

A light and citrusy example of a traditional Berliner Weise style (which dates back to the 1600s) is the 1809 Berliner Style Weisse. Created by Professor Fritz Briem and brewed by Weihenstephan & Doemens, it’s medium-bodied, delicately fruity, effervescent, musty, and very tart. At a basic 5 percent a.b.v., it’s not a huge beer, but between the barley and wheat malts and the fermentation character developed by the Lactobacillus, it boasts a complex combination of flavors and aromas.

Hanssens Artisanaal’s handsome Oude Kriek (6 percent a.b.v.) is a traditional fruit lambic ale, aged in oak with fresh cherries. Brewed in a town called Dworp, it’s a woody, tart beer that’s deep red in color. With a slight haze, Oude Kriek pours with light carbonation and a pinksh head that quickly diminishes. It’s puckery from start to finish. The cherry and oak flavors dominate, and there’s nothing sweet or sugary about it.

Another very traditional Belgian sour ale is the Lindemans Gueuze Cuvée René (5 percent a.b.v.), a sparkling, hazy champagne-like blend of young lambic (typically six months old) and more mature vintages of two to three years. Dry, crisp, and drinkable, it’s a sour beer of medium intensity.

An unusual rendition of a sour brown ale comes from the small-batch of Norway’s HaandBryggeriet brewery (or “hand brewery”), based in the city of Drammen. Presented as a “Norwegian ale aged in wine barrels,” their malty, slightly acidic Haandbakk is a dark brown ale with deep oak flavors and mild sourness. It’s a bit strong for the style at 8 percent a.b.v.

The smooth Duchesse de Bourgogne (6 percent a.b.v.) from Brouwerij Verhaeghe is a Flemish red ale with mild acidity. Aged in oak casks, it’s maltier and sweeter than the more wine-like lambics. The final bottled product is a fruity, pleasantly sour blend of young and old versions.

Currently, New Belgium Brewing’s La Folie (6 percent, a.b.v.) is an American-made sour style labeled as a “sour brown beer.” Aged in French Oak barrels between one and three years before being bottled, it was inspired by the red ales of Rodenbach, as part of the brewery’s Lips of Faith lineup. Puckery and highly drinkable, with a hint of caramel maltiness, it’s not nearly as intense and funky as some of the more acidic Belgian ales.

“Sour sounds like one specific thing to someone who’s not familiar with the style, but it comes in different shapes and forms,” says Shor. “Not all sours are that sour. It’s wide open.”