A brew day at The Libertine Pub (Morro Bay, California) is unlike one at any other production brewery in the country. Tyler Clark, the brewpub’s owner and brewer stands over a steaming kettle with a super-heated rock held in a pair of metal tongs. Watching through a pair of yellow safety goggles, he dips the lava rock into the steaming wort.
The smell of caramelized wort wafts up, and steam dances like smoke on the surface of the barely rippling liquid before rising up to the low-hanging rafters just above that are coated in grain dust accumulated over two years of pouring milled grain into the nearby mash tun.
Known as stein brewing (stein is German for stone), this process of using superheated rocks—instead of steam or a direct fire—to heat the wort makes The Libertine unique among American breweries. (Try your hand at stein brewing with Clark’s Tart Golden Ale Recipe.) Others have employed the process, but only Clark and The Libertine use it full time. And as fascinating as the process is, it takes a backseat in importance to everything that happens next—namely, the spontaneous fermentation and oak aging.
“We’re a wild brewery as far as we make wild ales,” Clark says. “We don’t use any pitching yeast. Everything is naturally from the environment around us. We use a coolship, and it’s all harvested. We don’t do any temperature control.”
All that grain dust in the rafters is rife with _Lactobacillus, Brettanomyces, _and other naturally occurring microorganisms, and it all plays a part in the production of The Libertine’s sour wild ales. While about a dozen or so lava rocks taken out of Morro Bay, which is right outside the pub’s windows, heat the wort to pasteurization temperatures and occasionally as high as a slight simmer, a five-gallon batch of hopped wort is brewed on the pub’s stove. The hops, harvested from the pub’s patio where they grow year-round, will lend their antiseptic and preservative qualities to the beer, but little flavor or aroma.
That side batch is added to the kettle after a 30-minute “boil,” and hot wort is pumped into a makeshift coolship as well as an open fermentor where it will chill overnight. No yeast is ever added, but with such a rich culture present in the natural environment at The Libertine, fermentation is off and running by the time Clark and his team are ready to transfer the fermenting beer into oak barrels.
“Let the brewery become its own microorganism,” Clark says. “We don’t have to pitch because we have so many live cultures here in the brewery. We’re at the same amount of lag time as we were pitching yeast and we don’t even need to pitch. The next day we’re already rocking.”
The oak barrels are crucial to the process and are cellared in a basement beneath the brewery. Clark sources the barrels from California’s wineries and distilleries, but also uses plenty of second-hand barrels that have been phased out by nearby Firestone Walker Brewing Company (Paso Robles, California).
The Libertine brews only four styles of beer: a Golden Blonde, a Red, a Saison, and a Porter. However, the lineup of beers on tap is nearly infinite, as those base beers spend a long time in barrels, often up to a year or more, aging on fruit or other ingredients. Then they are blended together to create something wholly new. It’s why Clark refers to himself as a blender more than a brewer.
“I’ll build a beer around one or two barrels that I like and try to enhance those flavors,” Clark says. “We might pull half a barrel from something we brewed two months ago, a barrel from something a year ago, and five barrels from a batch we brewed two years ago. It’s not like one batch is brewed, and that’s our Framboise.”
Indeed, the Libertine Framboise began as the brewery’s Golden Blonde but spent time aging on raspberries in the barrels. The beer, one of several that are bottled and sold out of the brewery, is a vibrant pink that pours with a fizzy, quickly dissipating pinkish head on top. It’s tart and effervescent with a pleasant crispness.
The Porter might be aged on coffee or spices or—in the case of Once You Gose— blended with a barrel-aged Berliner Weisse, aged with vanilla beans and cacao nibs, then blended with saltwater from the bay.
The Libertine’s Berliner Weisse, dubbed Berlinertine, gets its distinct flavor from the Lactobacillus bacteria present all over the brewery and barrels, but it is not fermented clean the way a traditional Berliner Weisse is. Of course, Clark and The Libertine aren’t exactly concerned with brewing to style or adhering to traditional methods—even if he does employ plenty of Old-World practices.
The aging and blending process means that The Libertine’s beers are essentially limitless in their variety. But they all share one trait—they’re all fermented with the same naturally occurring yeasts in the brewery, and they’re all unique to The Libertine, which is located in San Luis Obispo County.
“We’re not trying to re-create anything,” Clark says. “People call our beers ‘like Flanders’ or something. Well, we’re not Flanders. Lambic—same thing. It’s reminiscent of that. I’ve been trying to push the San Luis Wild Ales thing.”
If visitors aren’t wild about wild ales, the pub also has a few dozen guest taps that rotate through a selection of local beers and great choices from around the country. There’s also a bottle selection of about 200 beers available as well. But going to The Libertine and avoiding its signature sours would be akin to skipping beef at a renowned steakhouse. In drinking a wild ale at The Libertine, you not only take in the beer, you drink in Morro Bay itself. Finding a brewery as local-centric is difficult, and finding one with comparable methods and beers is impossible.