Bootleg Biologist Jeff Mello

Armed with test tubes, Petri dishes and pluck, Bootleg Biology’s Jeff Mello is on a quest to source yeast from every ZIP code in America.

Jeff Mello was fed up with his job. Yes, his post as a fundraiser for Washington, D.C., nonprofits was fulfilling, but work was a slog. “He was coming home and dreading going to work the next day,” his wife, Erin, recalls. At home, Mello had joy. He’d started homebrewing, marveling in yeast’s magical conversion of grain, water and hops into beer.

“Every Monday I’d tell my boss what beer I made that weekend,” he says. One batch led to another, an obsession quickly colonizing his brain. “The more I brewed, the more I realized that it was my passion,” Mello recalls. “So I quit.”
He had no compass, only a desire to explore the brewing world. After reading an article about lambic starters, Mello filled three mason jars with yeast-welcoming wort, crowned them with cheesecloth and placed the feast in his garden for a spell. He then stuck the jars in a closet.

“When I looked at them a few months later, they were completely nasty,” he says. The first jar smelled like creamed corn, while the second had grown something mushroom-esque. The third one smelled like… was that honey? “It had promise,” says Mello, who brewed with the yeast. The result was the intersection between a saison and a spicy hefeweizen, a beer that was familiar yet thrillingly new. He named the strain S. arlingtonesis, after his backyard in Arlington, Va., and started pondering the microscopic universe surrounding him. “If I could get yeast that made pretty good beer from my backyard, where else could I get them?” Mello says.

Last July, that whim became Bootleg Biology, an open-source endeavor to obtain and isolate microbes from free-range sources such as flowers, yogurt, walnuts, kimchi, beer-bottle dregs and even spruce berries from a Colorado amusement park.

“You can buy pure brewer’s yeast cultures, but I wanted to show people that you can source yeast from anywhere,” Mello says. Much like the unique characteristics imparted to grapes by soil, yeast expresses terroir. It’s the bugs fluttering across the Belgian countryside and settling in Cantillon’s coolship, Jester King’s wild ales made with Hill Country yeast captured outside Austin, and the microbes that Rogue brewmaster John Maier marshaled into the aptly named Beard Beer. “Yeast provides a sense of place,” Mello says.

Bootleg’s Backyard Yeast Wrangling Kits

To underscore that idea, he launched the Local Yeast Project. Its mission is amassing the world’s most diverse bank of microbes, one from every American ZIP code. Since there are approximately 43,000 ZIP codes (“I looked up the number once and decided that I’d never think about it again,” he says), he needed help. Lots of it. “I thought, if I’m going to make this project successful, then I really need to focus on teaching people to harvest yeast,” says Mello, who has since relocated to Nashville.

It was a superb plan, save for one flaw: In college, Mello majored in political science. His microbiology instruction was zilch. “It doesn’t necessarily make sense why I made that transition,” he says, laughing. “I just wanted to do something creative.” As a guide, he used Chris White and Jamil Zainasheff’s book, Yeast, and started playing around with agar plates (Petri dishes packed with nutrients to cultivate microorganisms) and a microscope. To his surprise, it was pretty simple to culture yeast.

“People assume you need fancy tools, but you can buy agar at international food stores, and Petri dishes are just plastic plates,” Mello says. To empower other brewers, he designed the Backyard Yeast Wrangling Tool Kit, containing all the tubes, pipettes and sterile swabs necessary to capture wild yeast.

“He’s freed yeast from the idea that it is something that you buy from a yeast lab,” says American Sour Beers author Michael Tonsmeire, who is testing Bootleg’s kombucha strain at San Diego’s Modern Times (he consults for the brewery).
Homebrew shops have also taken note. “With the kit, people can start capturing and using their very own house strain, making their beer even more personal,” says Andrew Jeske, general manager at Nashville’s Rebel Brewer. Each kit also contains an ulterior motive: If brewers isolate a strain, they can plop a cultured swab into a pre-paid envelope and mail it to Mello, who will deposit it in his bank.

Until recently, “bank” was fancy talk for the refrigerators crowding his basement. Mello had been running Bootleg Biology out of his home, where Erin works as a software product manager. After clocking out, she would head downstairs to help.

“It’s a mom-and-pop operation,” Mello explains. “There’s a lot of love and attention put into the tool kits.” But you can only package so many kits in your living room, and shoehorn so many fridges into your basement, before space becomes a concern. Hence, the couple opened a laboratory and workshop where Mello, who has since taken a microbiology course, can teach amateurs and pros to wrangle yeast.

Mello preparing Petri dishes

“Education is a huge part of this mission,” says Mello, a fan of Cosmos, the TV show that demystifies science. “It’s great when I hear, ‘I’ve always thought about doing something like this, but you’ve showed me that the science behind this is not too difficult.’”

Instead, the challenge is proving Bootleg Biology’s economic viability. Homebrew stores, bottle shops and breweries are tested beer concepts. “If you make a yeast lab filled with microbes sourced from different parts of the country, there’s no guarantee that it will be successful,” Mello says. There’s also no assurance that his cultures can create great beer. That requires real-world trials, and Mello can only brew so much of his base saison (pilsner malt and a bit of wheat, lightly hopped) to determine tastiness.

To help, he happily doles out cultures for brewers and clubs to test-drive, asking only for the nitty-gritty fermentation data. Down the line, Mello hopes to propagate and sell successful strains.

After all, there’s always more yeast, whether it’s from cacti he swabbed while on family vacation in Arizona, or seeking out microbes in a different Nashville neighborhood.

“We’re Boy Scouts when it comes to gathering yeast strains,” says Erin, who stashes test tubes in her purse and glove compartment. Always prepared. It’s a good motto, especially in Mello’s eternal endeavor. “Even when we get yeast from every ZIP code,” he says, “there will still be more to collect.”

MELLO’S ESSENTIAL BEERS: 1. Orval Trappist Ale “It’s the beer that introduced a lot of people to the wonder of Brettanomyces, and the first funky beer I ever drank. It instantly brought to mind a favorite musty, old bookstore. I was completely entranced from that moment on.” 2. Dogfish Head Ta Henket “It’s truly amazing how Dogfish Head and Patrick McGovern decided to capture this beer’s yeast directly from the wild in Egypt. That really is a testament to the idea that you can’t make a beer specific to a local area without locally sourced yeast.” 3. Cantillon Gueuze “I can’t think of any better example of the beauty that can be produced by local, wild microbes than traditional lambic. Cantillon Gueuze certainly sets the bar high for the rest of the world.”