Inside the Maniacal Yeast lab in Bangor. Photo courtesy of Maniacal Yeast

As far as beer ingredients go, hops get all the glory, malt is having its moment, but yeast is the unsung hero of beer.

Yeast is what makes beer beer. This little microorganism – part of the fungus kingdom – feeds on the sugars from malt and creates alcohol as a byproduct of the fermentation process.

“Without (yeast), you’d just have a nonalcoholic malted beverage,” said Justin Amaral, owner of Bangor-based Maniacal Yeast.

Yeast has another important job in beer.

Microscope looks at yeast and bacteria. Photo courtesy of Maniacal Yeast

“Yeast also produces a massive amount of different acids and flavonoids, a lot of those flavors you pick up in a beer,” said Amaral. “If they’re not hop-driven or malt-driven like a stout or a barley wine, they’re generally from all the microbes living in the beer.”

Amaral has been working with the microscopic world of beer for the last eight years. With an IT background, he first became interested in yeast when he began making his own wine and started doing what he called his science projects to find the best nutrients, or food, for wine and mead yeast.

“I started reading a lot of books about it, and a couple of years in, I decided to get really down the rabbit hole,” Amaral said. “I started reading published papers, talking to college professors – basically everything you would do for a microbiology degree, but I was doing it on my own time.” Three years later, he had his own yeast lab in his basement, where he experimented for another two years before he felt he had enough knowledge to open a commercial lab.

Maniacal Yeast, launched in 2018, houses 3,600 different types of yeast and bacteria in its bank. Amaral works with more than a thousand breweries all over the world and more than half of Maine’s 161 breweries. He’s even worked with a Hawaiian brewery to grow out yeast captured in space by NASA for a beer.

Amaral’s day-to-day looks a lot like working in a brewery, except he discards the beer and saves the yeast.

“What a yeast lab does at its core is bank yeast strains, which basically means to hold onto a yeast strain in a cryo-freezer at negative 80 degrees Celsius, so it lasts forever, essentially,” he said. “And then we hold onto those strains until a brewery or winery contacts us looking for a specific strain or maybe a mixed culture.”

If a brewery is interested in making a beer with a certain flavor profile, Amaral can find a yeast in his collection that matches what they’re looking for. He then thaws the yeast strain and grows it out until it is the right size for that brewery’s tanks.

Justin Amaral, owner of Maniacal Yeast. Photo courtesy of Maniacal Yeast

Maniacal Yeast also does analytics for breweries, testing for microbial types and measuring things like color, alcohol by volume, amount of bitterness, amount of haze, calories and acidity.

If you’d like to sample a few beers that really play to yeast’s characteristics, Allagash Brewing Co. is a great place to start. Its Belgian-style Coolship Series collects the naturally occurring yeast from the air for spontaneous fermentation in an open-top vessel called a coolship.

Brunswick’s Moderation Brewing Co. is another. They use a strain of Kveik, a fast-fermenting Norwegian yeast that’s rising in popularity, in many of their beers. Maniacal provided the initial strain that has developed into their house yeast. Find it in Pat, a hazy Norweigan IPA.

Amaral also suggests trying beers from Norway Brewing Co. “They’ve used some interesting strains we have and always come up with interesting ways to use them,” Amaral said. Try the Inglorious Bastard farmhouse ale or Berliner Weisse sour.

Farmhouse ales, like saisons, and any wild fermented or sour beers are all styles where yeast plays the leading role. They vary greatly in the funkiness and sour spectrum, so it’s worth trying several until you find one that jibes with your taste buds.

Sometime next year, look out for Amaral’s own brewery in Vassalboro, where he’ll also move the lab. It’s no surprise Sidereal Farm Brewery will focus on yeast-forward spontaneous fermentation brews.

Catie Joyce-Bulay is a Winslow-based freelance writer who recently moved back to her home state. Find her writing on beer, travel and people pursuing their passion at or Twitter: @catiejoycebulay.

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