CRAFT BREWERIES ARE LETTING WILD YEASTS TAKE OVER
Why Colorado craft breweries are letting wild yeasts flavor their brews
For centuries before the advent of modern brewing, early Scandinavian beer-makers coveted their “magic sticks,” special stirring utensils that miraculously turned otherwise ordinary liquid into beer.
Thanks to French biologist Louis Pasteur, today we understand that the brewers’ sticks were not, in fact, magical, but were teeming with yeast and bacteria that went to work converting the liquid’s fermentable sugars into alcohol and creating bubbles (carbon dioxide) in the process.
“From a historical perspective, everything was spontaneously fermented,” said Chuck Skypeck, technical brewing projects manager for the Boulder-based Brewers Association.
“From the time beer began being brewed, it was being brewed with basically whatever floated into it and fermented it. And that’s spontaneous fermentation.”
These days, most brewers don’t leave so much up to chance. They buy yeast that special beer scientists have isolated and then propagated in a lab, which allows them to select exactly the right strain to make the beer style they want.
But some breweries, including a handful in Colorado, are perfecting the art of spontaneous fermentation, a time-honored process that harkens back to beer’s earliest days. With spontaneously fermented beers, they’re letting nature do its thing — whatever yeast and bacteria find their way into the wort dictate the eventual
beer’s flavor and characteristics.
As you might expect, the process can be unpredictable and doesn’t always go to plan. But when they get it right, brewers are making some seriously delicious spontaneously fermented brews that beer-drinkers are willing to travel from miles around to taste.
When James Howat opened Former Future Brewing Company in Denver in 2014, he mostly made standard beers — IPAs, stouts, etc. — but began experimenting with spontaneously fermented beers on the side.
His new brewery could only afford to enter one beer into the Great American Beer Festival that year, so Howat decided to take a risk and enter one of his so-called “black project” beers, named for their under-the-radar status, even among the brewery’s staff. His beer won a bronze medal in GABF’s “experimental beer” category.
When Howat began doing monthly bottle releases of
“black project” beers, people lined up around the block for a chance to buy some; beer-drinkers traveled from other states.
By August 2016, it became clear to Howat that he was onto something special. He decided to stop making standard beers, rename the brewery (to Black Project Spontaneous and Wild Ales) and focus exclusively on spontaneously fermented brews.
“To this day, on a given night, a solid percentage of (customers) are not from Denver; they’ve traveled to try our beer,” said Howat.
Howat, who studied biology at Colorado State University and spent five years as a high school science teacher, has always been fascinated by spontaneous fermentation.
With beer, the process generally goes like this: In late fall, winter and early spring, brewers make and boil wort — sugar water made from grains and hops — then transfer it to a large, shallow, open-top vessel called a coolship overnight. They typically open the windows and doors so that the crisp night air can help the liquid cool rapidly. (When Howat first started making beer this way, he pumped the wort up to a coolship located on the brewery’s roof.)
As it cools, the liquid is inoculated with random yeast and bacteria strains floating by on the breeze, dropping in from the brewery’s ceiling or wherever else it’s been living nearby. This part of the process gives spontaneously fermented beers terroir, a word that’s often used to describe how local factors — climate, soil, geology — influence the final flavor of wine.
The particular yeast and bacteria strains that find their way to Howat’s beer on South Broadway are likely not the same ones inoculating beer made somewhere else, which gives each beer a unique local fingerprint.
The next morning, the liquid goes into a sterile barrel, where it ages for as long as the brewer wants, often one to three years. In the barrel, the liquid goes through a complex transformation involving various boom and bust cycles of different microorganisms that each contribute something unique to the final beer, Howat said.
“Standard fermentation is basically ‘yeast ranching,’ ” Howat said. “You have to understand the one strain of yeast you’re using to make your IPA. If regular brewing is yeast ranching, spontaneous fermentation is more like rainforest ecology. There are almost innumerable species and you have to try to understand the interactions between them all and how to set up an environment for all of them to thrive. You have to treat it as a whole. It’s trusting a community of microbes to continue and progress in a way that makes the beer taste good.”
Once happy with the beer in each barrel, the brewer typically blends different barrels together to achieve the desired final flavor profile.
As much as he loves the science behind this beer, Howat also revels in the artistic process of blending.
“Brewers aren’t necessarily cooks — you don’t get to taste it as you’re making it and say, ‘It needs a little salt or pepper,’ ” he said. “To me, the art that inspires the most is sitting down with 100 barrels, selecting some and then blending from those, deciding whether to put fruit or hops in it.”
Unfortunately, the final product doesn’t always taste good — Howat dumps roughly 20% of the beer he makes, but that’s to be expected, he said. That lost time and money is likely a big reason why more brewers aren’t pursuing spontaneous fermentation, along with its long process and unpredictability.
These beers are also typically tart in flavor, which just doesn’t appeal to everyone.
Even so, Lisa and Brandon Boldt decided to take the plunge and focus solely on spontaneously fermented beers when they opened Primitive Beer in Longmont three years ago, though they both still have jobs elsewhere and the brewery’s taproom is only open for a few hours on Saturdays.
“Neither of us takes a paycheck from Primitive, we have zero employees, we have fulltime jobs,” said Lisa Boldt. “It’s really a passion project that we do because we love it and we believe there aren’t enough breweries making spontaneous beer, and there’s a place for us in the industry.”
After earning master’s degrees in geology, the couple decided to take a year off to pursue their hobbies while planning their wedding before applying to jobs or doctoral programs. As longtime homebrewers, they got jobs at Lafayette’s Odd13 and realized they wanted to make a career out of beer.
They fell down the spontaneous fermentation rabbit hole, drinking whatever beers they could find and taking trips to Belgium, where many familyrun breweries have been spontaneously fermenting beer for decades. (In Belgium, these are called “lambic beers.”)
“The beers are incredible; they’re kind of magical,” Lisa Boldt said. “You’re not adding yeast and bacteria, and it just happens. It’s spontaneous. You’re adding this sort of soup to a vessel and then all of a sudden it turns into beer. It’s really, really cool. So it became our obsession.”
What started as a small side project quickly morphed into a full-scale operation, complete with a 4,000-square-foot taproom in Longmont’s mixed-use Prospect New Town neighborhood. Today, Primitive ships its beer to 22 states and has gained a dedicated following of spontaneous fermentation fans. The Boldts hope to expand the brewery’s fan base and attract people who are interested in other naturally produced beverages like wine and cider.
“We’re at this point where people are more focused on production techniques and flavors than what its classification is,” Brandon Boldt said. “Our consumers are more interested in spontaneous fermentation necessarily than beer itself.”
To that end, Primitive is experimenting with wine-beer and cider-beer hybrids, as well as spontaneously fermented beers aged on wine grapes and a special craft vinegar project.
“It’s very much actually going back to something that would have been traditional,” Brandon Boldt said. “It’s a return to some of those rustic traditions and some of the rituals that had been passed down. There’s a magic to it, there’s a rebellious nature to it, and yet, at the very core, it’s about very low intervention, letting the yeast and the microbes do the work for you. It’s a patient, long kind of beer-making.”