A battering ram of carbon dioxide punches me in the face and leaves me coughing for air. It’s been trapped inside its wooden tank prison for a little over two years now, the byproduct of a long, slow Berliner weisse fermentation, and it’s not wasting any time getting the hell out.
“Yeah, it’s no joke,” says Jace Marti, head brewer at Starkeller Brewery in New Ulm, Minnesota, and assistant brewmaster / sixth-generation brewer in the August Schell Brewing Company lineage. We’re peering into the narrow oval hatch at the base of one of his 12-foot-tall, 10-foot-wide cypress wood tanks, which serves as the barrel’s sole entry and exit point. Jace shines his headlamp toward the top of the tank and points out two distinct pellicle rings made of hardened Brettanomyces yeast (a key player in mixed-culture fermentation*)—one marks where the beer reached when it first entered the tank two years ago, the other demarcates how much beer was left when it finally finished fermenting a few days ago.
Soft-spoken and eager to teach, the 35-year-old has been a part of Minnesota’s beer scene since he was a kid. Jace and his younger brothers, Kyle and Franz, grew up in and around the iconic Schell’s brewhouse, learning the ropes from their dad, Schell’s president Ted Marti, and the dozens of employees who keep the second-oldest family-owned and -operated brewery in the United States running. Where constant exposure to the family business might have turned some people off, Jace says it solidified his desire to be a brewer. Not because he felt like he had to be one, but because he wanted to. “We were all involved early on and got to do fun stuff, and it was always like a big family. It still is today,” he says. “But when we did start, we started at the bottom.”
He’s far from the bottom now, largely thanks to the traditional Berliner weisse beer he’s making at the Starkeller. Located on the outer edge of New Ulm, the Starkeller strikes the opposite impression as its Bavarian Wonderland-esque parent brewery. More or less a glorified pole barn, the only clue that this white-metal rectangle has anything to do with the renaissance of a beer style that nearly went extinct is a tiny black logo and the word “Starkeller” painted on one of its corners. Step inside, however, and everything comes into focus.
Antique tank parts and brewing tools line the walls leading into the taproom, all recovered by Jace from the Schell’s brewery as he unearthed the main features of the Starkeller: 10 massive, 83-year-old, dark-brown wooden tanks that, in his mind, were destined to cultivate Berliner weisse beers so traditional, even breweries in Berlin have given up on them.
Up until 1991, the tanks were used in Schell’s regular production, mostly to make Deer Brand. Coated internally with brewer’s pitch and never exposed to the highly volatile Brett yeast that now cozy up inside of them, the last beer made in the tanks before they were decommissioned (and subsequently rescued by Jace in 2008) was Pete’s Wicked Ale—one of many beers Schell’s contract brewed at the time. Today, their sole duty is to ferment and age funky, mixed-culture sour beer.
Getting the tanks to a condition where they could do this involved hazmat suits, dry-ice blasting, rehydrating, and lots of advice from master cooper Russ Karasch of Black Swan Cooperage. It also required getting the okay from his dad. “Yeah, it was not something that an old, traditional brewery just jumps on board with,” Jace says. “It took a couple years to convince him.”
Pitching his dad involved sampling sour beer—a lot of it. Every time Jace traveled, he’d bring as much sour beer back to Minnesota as he could and taste through it with his parents. For a long time, it didn’t work. But then, while drinking a Rodenbach Grand Cru at Town Hall Brewery in Minneapolis with his dad, it finally clicked. “That was the one where he was like, ‘I get it,’” Jace recalls. “The sweet and sour, the malt character: that’s when he said he could see where it could be a thing.”
Before jumping all in with the Starkeller, Jace restored just one tank and, in 2012, made Star of the North, a 3.5% ABV Berliner weisse that was released in 2013. It was unlike anything anyone else in Minnesota—or the U.S.—was making at the time. “I remember going on Beer Advocate when we launched Star of the North and there were 42 other Berliner weisse beers on the whole site—that was including German breweries,” Jace recalls. “Now there are something like 3,000,” most of which are kettle sours**. (The list included 3,895 at the time of printing; Star of the North was 22nd in ratings.)
During that time, Jace keeps an eye on the beer’s gravity, pH, and total acidity levels. Once they begin to level out, then it’s all about sensory testing, which is done about once a month, “because you’ll drive yourself nuts with all the ups and downs that it goes through.” Once the beer is deemed ready, it is either bottled and kegged immediately or transferred back into stainless steel tanks to continue aging with a fruit addition.
It’s a painstaking process, made even more so due to the fact that all of the Brett yeast strains Jace uses were cultivated from original Berliner weisse bottles he collected while studying at the Versuchs und Lehranstalt fuer Brauerei in Berlin (Research and Teaching Institute for Brewing in Berlin) in 2011. Moreover, when made the long way instead of using the kettle-souring shortcut, Berliner weisse is unpredictable. Brett is fussy. Wooden tanks develop cracks. Waiting years instead of weeks for a beer that may or may not turn out as planned is risky.
But those are all just sidenotes to Jace. “[Traditional Berliner weisse] is basically a dead style; even today there are only a couple breweries doing it,” he says. “But I wanted to do it. With our focus on German-style beers, the tanks are a way to utilize a piece of our history in a new way.”
While Jace has been carefully developing his hyper-traditional, slow-and-steady-does-it sour beer program at the Starkeller, kettle souring has sprinted into fashion among drinkers and brewers around the U.S., flooding the Berliner weisse category with beers that technically qualify as such, but are far from being mirrors of their ancestors. This is largely due to the gaping flavor chasm between traditional sours and kettle sours: Whereas the former achieves a complex range of flavors thanks to the variety of microbes that participate in the process, kettle sours are one-note wonders: tart.
Jace is torn about the rise in popularity of kettle sours; they could either serve as stepping stones for brewers to eventually pursue mixed-fermentation sours, or they could continue to dominate the market in such a way that brewers don’t see a point in doing it the traditional way. Another reason a brewer might opt out of making a Berliner weisse the way Jace makes a Berliner weisse: the cleaning situation—a solid 10-hour process to empty, vent, clean, and purge each tank.
Jace tucks in his shirt, straps on his headlamp and goggles, grabs a hose, and gathers a hand brush, extended-arm scrub brush, and bucket filled with cleaning solution near the opening of the tank, which has finally been cleared of CO2. “You’re going to be my spotters,” he says to us with a hint of amusement. Then he wriggles head-first into the tank and starts scrubbing.
Editor’s Recommendation: Starkeller’s Binary Storm
This mixed-culture Berliner weisse was aged for over a year in a cypress tank, then spent six months in stainless steel accompanied by 5,000 pounds of boysenberries. After another six months spent bottle- and keg-conditioning, the result is a deep-purple beer with bright acidity and a jammy berry character. A solid summer refresher.
*Mixed-culture fermentation uses a combination of Saccharomyces (brewer’s yeast) and other microbes, such as Brettanomyces (wild yeast), Lactobacillus (lactic acid–producing bacteria), and Pediococcus (lactic acid–producing bacteria), to make sour beers. The Starkeller uses all but Pediococcus. Back to story
**Kettle souring, also called quick souring, takes just days instead of years. To achieve the souring effect, wort is boiled, cooled, and dosed with Lactobacillus—a probiotic that converts sugars to lactic acid—right in the stainless steel brew kettle. It then sits for a few days in the kettle while the liquid acidifies. Once the desired level of tartness is achieved, it goes through the normal brewing process (boil, hop addition, cooling, and fermentation with brewer’s yeast). Back to story