Atlanta’s SweetWater started in 1997, building a successful business on the back of its easy-drinking flagship, 420 Extra Pale Ale. Last year, the brewery constructed a 37,000-square-foot structure—stitched to SweetWater’s packaging room—dedicated to barrel-aged beers agog with Brettanomyces and souring bacteria.

The Woodlands Projects lets SweetWater “continue to push the envelope and add beers to our portfolio that are completely different,” says owner Freddy Bensch. The initiative gives brewers broad freedom for flavorful exploration. “We’ve got some of the best brewers in the country. It’s just continuing what we’ve done. It’s having fun and being creative.”

SweetWater’s sour trials are also benefiting its core production lineup. Woodlands lead brewer Nick Burgoyne put test batches of Tropical Lover—a Berliner Weisse with guava, mango, and passion fruit—on tap, and the positive feedback led SweetWater to release it in cans this spring. “It’s getting people’s feet wet to the idea of sour beer,” he says.

While Lover will see wide distribution, Woodlands beers such as Through the Brambles, a blackberry sour ale, are released in limited batches. (SweetWater created just 928 cases.) Scant quantities mean the beer will never fuel SweetWater’s economic engine—and that’s OK.

“We’re not relying on this as a revenue stream,” Bensch says. “It’s more, ‘Let’s have fun with this and do crazy, impactful things. Let’s see where it goes.’"

Adding a sour and wild program can also lend prestige. Cincinnati’s Rhinegeist was founded in 2013, growing to America’s 33rd-largest Brewers Association-defined craft brewery on the strength of its Truth IPA. This April, Rhinegeist unveiled its Outer Reaches Sour Ales program, featuring beers such as the nicely acidic Infinite Dawn Blonde.

The program’s roots date to Rhinegeist’s early days, and the brewery even isolated a particularly fruity Brett strain from its building. However, Rhinegeist decided to bide its time until it could enact sanitation protocols.

“We weren’t going to scale this up until we had a better plan about how this wouldn’t infect the rest of the brewery,” says co-founder Bryant Goulding, the brewery’s vice president of sales and marketing. “That’s a piece that stops a lot of breweries.”

Rhinegeist installed operations in its basement, the production a blip in the brewery’s big picture. “We’ll push 100,000 barrels this year, but we’ll do less than 200 barrels of sour beer,” Goulding says. “It’s not a volume play, it’s a credibility play.”

Today, breweries may endear themselves to beer enthusiasts by making hazy, soft IPAs, but that’s no longer enough to hold an always-wandering consumer gaze. Great IPAs are everywhere. Great wild beers, well, they’re not so common. They’re an important marker of top-shelf fermentation talent, a brewery that cares enough to take months and months to make a beer, not just another double dry-hopped whatever brewed, canned, and sold in a couple-week timeline.

ChurchKey’s Engert sees another reason why beer makers may enter this sphere.

“Many of these breweries are finding ways to spread out their excess volume, in ways that are still limited and delicious,” he says. That means looking at beers that might travel best. “If you’re sending a palette of beer once a quarter to New York City, you’re more likely to send your mixed-ferm stuff instead of IPAs.”