A Yearning for Wild Yeast at the Arrowood Farms Brewery
Wort, the name for unfermented beer, is basically sugar-water mixed with oily hop resins. Not long ago, Jacob Meglio, head brewer at Arrowood Farms in Accord, N.Y., filled some glass jars with this unremarkable liquid.
Then he went for a walk.
To transform wort into beer, you need yeast. Most brewers buy domesticated yeast strains from a supplier, or they culture their own strains in-house. Some, particularly Belgian breweries, rely on wild, airborne yeast to settle on big tubs of wort in a process called open-fermentation.
When Meglio trudged through the woods that day, he was in search of the wild yeasts floating around the farm. But collecting yeast isn’t like tracking a wild animal. If anything, the process is less about capturing the yeast than receiving it.
“It’s kind of a spiritual experience, where you wander out into the woods on the farm. You’re standing in a forest with cedar, oak and maple trees, and they’ve been there for millennia,” he says. “We’re going there and leaving jars at the bases of trees and hoping these little microscopic invisible fairies land in them.”
Meglio set down the jars in various places, guided more by intuition than anything. “It’s completely a gamble. You look around. You smell the air. Then you leave the jars out in the open,” he says. “You could end up with so many different things. It’s a nod to the probability gods. Give me what you’re going to give me. I’m just waiting.”
Over the next day or two, Meglio collected the jars. The liquid in jars that look promising got thrown into small carboys fitted with airlocks, then left for a few days to propagate.
“You might get some mold or fungus. You might catch a field mouse. If all is well, you recognize it as yeast,” he says. “By the way, there are many asterisks here. It’s not necessarily dangerous, but we also have to test for things like bacteria that’s not safe for human consumption.”
Low-Intervention Brewing
Why go to all this trouble? For Meglio, this was the natural evolution of the farm’s “low-intervention” brewing philosophy, which goes hand-in-hand with New York’s Farm Brewing Law.
Because the bill requires a significant amount of ingredients to be sourced from the state’s agricultural producers, farms already had an incentive to think regionally. “We started in that climate, as a brewery designing recipes to highlight the agricultural components that make up our beer,” he says. “We wanted to do straightforward, approachable beers that showcase this area.”
For example, the brewery draws water from the Widow Jane Mine, an abandoned cement mine. “The calcium in the mine seeps into the water. The hardness allows us to do a New York take on a traditional German style Kölsch. Our recipe is designed to showcase the water, which is an unsung ingredient,” says Meglio.
Likewise, he says, the brewery’s pale ale recipe is designed to showcase Cascade hops that are grown on the farm. “It’s interesting to try our version compared to well-known West Coast examples that use the same type of hops,” he says. “There’s more of a piney, cedary character in ours, due to different moisture contents, soil conditions and so on.”
Meglio acknowledges that ‘low-intervention’ brewing means a slight trade-off in consistency. “If you order our Kölsch next summer, it’ll be the same beer, but with slight variations. It’s a dialogue between the seasonal variety of our ingredients and consistency,” he says.
“We’re more interested in using natural ingredients that we don’t have to tweak in any way. We’re not treating our water. We’re not using refined hop oils. If one IPA is a little more bitter than the last, that’s okay. Beer is an agricultural product. We want continuity, but we also want the natural character of the ingredients to come through.”
Yeast-Driven Regional Beer
That brings us back to the harvesting of wild yeast. I talked to Meglio the day before the next step in the project – a trip to his alma mater, SUNY-New Paltz, where he studied chemistry and biology. The farm is partnering with the university’s lab to separate the yeast strains collected in the jars.
“People in our industry are really starting to talk about terroir and regional flavor,” he says. “They’re talking about grain and hops, but the real magic happens when we work with the yeast in our region. That’s what I’m excited for.”
Most likely, the jars of yeast Meglio collected contain different strains, so the next step is to separate them. “We’ll dilute the blend to a very specific ratio and spray it on an Agar plate. The idea is you’ve diluted it down enough so that when it starts to propagate again, you’ll see colonies start to form, and each colony comes from a single ancestor.”
From there, Meglio can build up big enough samples to pitch into batches of wort, to determine what flavors each strain contributes. “Eventually, we’ll be able to blend them so no one character or flavor is overwhelming,” he says. “When you get these wild blends of yeast, you get whole layers of complexity. When I think about regional flavors and where we stand now, that’s what I think about. We still haven’t quite seen what it’s going to be, and I’m excited to find out what we learn.”