Breakout Brewer: Mystic Brewery | Craft Beer & Brewing

Breakout Brewer: Mystic Brewery

With a focus on spontaneously fermented beer, Mystic Brewery Founder Bryan Greenhagen embraces the risk and reward of wild yeast to create distinctly American beer.

Emily Hutto 4 years ago

Breakout Brewer: Mystic Brewery Primary Image

Bryan Greenhagen, who founded Mystic Brewery in Chelsea, Massachusetts, outside of Boston, compares his brewery to the French bread company, Poilâne circa 1932. When Parisians started mass producing white bread after World War II, the bread maker Lionel Poilâne continued making an artisan country loaf, “what they would consider real French bread,” says Greenhagen. “There was this big campaign—much like our craft-beer campaign against light fizzy yellow beer—against the white loaf of bread.”

Greenhagen’s beers are anything but fizzy yellow lagers. His lineup of farmhouse-inspired ales is comprised 90 percent of barrel-fermented saisons. Much like Lionel Poilâne, he’s committed to old-school techniques in what’s become a very industrialized sector. “We went back in time,” Greenhagen says about his brewing practices. “So basically, the realization [is] that people use their local yeast and propagate their own.”

Greenhagen and crew developed a house yeast strain when they were waiting for their brewing license to come in, establishing early on that Mystic’s focus would be on fermentation. The brewing license arrived in 2010, and since then Mystic has been explaining to customers and fellow brewers why a brewhouse did not appear. To hone in on what he thinks is the most important part of the brewing process, Greenhagen contract brews his beers off-site in eighteen-barrel batches, transfers wort to a truck, and drives it back to Mystic for fermentation. “If you want to spend your money on barrels and time [on cultivating yeast],” Greenhagen says, “then it’s a great thing not to spend another $500,000 on a brewing system.”


Mystic now has a one-barrel pilot system where Greenhagen brews test batches. “There’s a big risk in brewing eighteen-barrel batches of spontaneously fermented beer,” he jokes. “You don’t want to do that. You want to start really small.”

Greenhagen got interested in spontaneous fermentation making bread at home. “I tried to make my own sourdough to find that there’s a bit of mythology going on with the idea that cultures come in on a wind. The first batch was disgusting. It tasted like puke,” he remembers. His point is that yeast is everywhere. However, yeast cultures that yield desirable flavors are hard to come by and take time to nurture. “Spontaneous fermentation means you have a living barrel, and the key is that you don’t add yeast. Maybe it’s in the wind, but it’s really in the room. It’s an uber-local terroir thing,” he says.

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The barrels at Mystic are reused to create a hospitable environment for wild yeast. “The idea is that you start the culture spontaneously, and then you keep cultivating it to adjust to your environment so that it actually tastes good. You have to work with it, get it to where you want it to go, and stabilize there,” he says. For Greenhagen, a brewery is not its brewhouse; a brewery is its yeast, an esoteric blend of localized organisms that distinguishes it from the rest.


Developing this blend is not an easy process. It’s expensive and time consuming. “If I calculate out how much it cost to develop our first native strains . . . well I won’t,” Greenhagen says. “It was a lot of work and a lot of time.”

With the brewery now in its fifth year, Greenhagen is still putting a lot of work and time into what he calls “fermentation-oriented adventures.” One of these adventures was the Mystic Entropy, a beer fermented in four stages with four different yeast strains: Mystic’s house strain, French white wine yeast, sherry yeast, and English barleywine yeast. Another more recent project involved culturing a completely wild strain of yeast off the grain itself.

“I went to agriculture school,” Greenhagen says. “Working with yeast is like indoor agriculture. I feel like I finally got my farmer rights by being a barrel farmer and farming microbes.”


Greenhagen isn’t just farming local microbes; he’s participating in a new wave of breweries focused on old-world practices. “It’s not the pale ale brewery model from the 1980s, and we’re not trying to make Belgian-style beer,” he explains. “We’re just trying to use techniques that pre-date the United States. Instead of trying to be Belgian, we’re trying to be a real-deal American brewery.”


Mystic is now on tap at the Mystic Beer Cafe at the brewery. This change required an extension license that allowed the brewery to serve full pours instead of two-ounce tasters. The brewery distributes primarily in Massachusetts and Vermont with specialty distribution as far as California and Washington.


Table Beer

4.3% ABV
A medieval-style field saison with flavor derived from Mystic’s house yeast

Mystic Saison

7% ABV
Mystic’s first beer, a traditional farmhouse ale made with barley, wheat, oats, and Hallertau hops

Saison Renaud

6.5% ABV
Brewed with the ingredients of a Czech-style pilsner with pilsner malt and Saaz hops

Will o’ The Wisp

6.5% ABV
An autumnal saison with a dry, nutty rye malt character that is accented with brown sugar and spiced with American and Slovenian hops