BY MORGAN FECTO | PHOTOGRAPHS BY LUCY HEWETT

At abbey breweries in Belgium, the monks leave the windows open to let in the breeze. It sweeps the naturally occurring yeast that clings to the rafters’ cobwebs down into their open fermenting vessels. The result is a sour ale that can’t quite be brewed any place else.

For Trevor Rose-Hamblin, head brewer and co-founder of Old Irving Brewing Co. in Chicago, the monks’ long-practiced methods for creating one-of-a-kind beer are an inspiration. “The brettanomyces are just hanging out inside of these cobwebs, and the monks won’t touch them because every time the wind blows it’s inoculating their beer,” says Rose-Hamblin. “It’s what makes Belgium so special to me.”

Rose-Hamblin’s reverence for tradition is present in every part of his approach—whether it’s geeking out over yeast varieties, making a by-the-book Oktoberfest, or designing Old Irving to feel like a real neighborhood brew pub. Still, that influence hasn’t curbed his need to experiment in his brew house. At Old Irving, his beer is wild in flavor, chef-y in technique, and Chicago in terroir. Tinkering with small batches of sous vide beer is one way he keeps an eye toward the future. “I found this beautiful bourbon vanilla chai, and I’ll actually take a little bit of the wort, which is the unfermented beer, and I’ll mix it with the tea and sous vide it with red kuri squash to leach more flavor into it,” he says. “Then I use lactose, which is almost like adding cream. What you get is a squash-chai stout with a milky backbone to it, like you’re having tea with milk.”

His Turtleneck Sweater stout benefits from sous vide in two ways. The process intensifies the flavors and speeds up the creation of sugars needed for fermentation, referred to by brewers as the “starch-to-sugar conversion.”  And it doesn’t stop at chai. Sous vide helps Rose-Hamblin brew his Rat Pack, a Belgian-style dubbel with flavors reminiscent of an Old Fashioned cocktail—cherries, orange, and whiskey.

“As a brewer, I can’t just dump straight whiskey into my beers—it’s completely illegal,” he says, laughing. “So what I do is I take these staves from oak barrels, then I’ll vacuum seal them with a little bit of whiskey, and I’ll put them in an immersion circulated bath.”

Culinary techniques are nothing new to Rose-Hamblin, who cut his teeth fresh out of culinary school at Homaro Cantu’s Moto, then as general manager at iNG, another of Cantu’s gastronomy-focused restaurants. While at iNG, Rose-Hamblin’s passion for home brewing led him to experiment with beer pairings and collaborate with local breweries. In his off time, he learned much by observing the ins and outs of brewing at Flossmoor Station Restaurant & Brewery in Illinois.

Given Rose-Hamblin’s background in modernist cuisine, it’s no surprise that Old Irving’s beers can be cocktails, or that its cocktails masquerade as beers. Rose-Hamblin brought on bar manager Matt Greene to mastermind beer cocktails with hops infusions, simple syrups made from wort, and Old Irving’s finished brews as starring ingredients.

“We have a Negroni on right now, and Matt will take a genever, which is almost like a gin, and he’ll infuse it with mandarina hops,” Rose-Hamblin says. “Once it’s carbonated, he’ll run it through our draft line so it comes out of the tap thick and creamy like a Guinness Stout would. When you’re having this thing, you’re tasting hops, you’re having that bitterness, a little sweetness, and it’s kind of mindblowing with that velvety texture.” Other inventive concoctions include the Hopaloma—a draft cocktail with tequila, grapefruit, mosaic hops, and Rose-Hamblin’s Scentinel IPA—and the Saaz-erac, which combines rye whiskey and absinthe infused with Saaz hops. Old Irving’s fare is equally surprising, with a kitchen full of culinary talent and critically acclaimed chef Matthias Merges of Yusho and Mordecai as a chef-partner.

From Rose-Hamblin’s perspective, brew pubs should borrow from the German tradition of selecting high-quality ingredients for both food and beverage. To him, that means looking to local and specialty vendors. “Right now I have the House of ‘Pagne’ on the menu, which is a collaboration with Pipeworks Brewing in the city,” he says. “We used white peaches from Seedling Farm out in Michigan, and we added that as a purée. We also added liquid Belgian candi sugar, which kind of dried it out. So you get this kind of Champagne-y Belgian ale.” Old Irving is as thoughtful about its sourcing as it is about reusing some of the by-products of beer brewing. A few dishes even utilize Rose-Hamblin’s “spent grains,” the grains left over from the mashing stage of brewing. “With a lot of our spent grains, we make a granola that we serve as a garnish on one of our desserts. We also make a spent grain sourdough because we have our own in-house baker who bakes all of our breads—burger buns, pretzels, and the spent grain loaf,” he says.

Some of Old Irving’s spent grains get a second life as animal feed or as fodder for laboratories in need of their unique proteins for classified experiments. Rose-Hamblin will even donate spent grains to customers who ask, and will give the yeast left in the bottom of his tank to the local Homebrew Club. “Brew pubs have always been about community,” Rose-Hamblin says. “They’ve always been that way. It’s not a bar. It’s a pub. It’s different.” And while Old Irving strives for that classic vibe, what’s new and exciting at the brew pub changes constantly—this month, it could be a beer brewed with rare candy cap mushrooms, then next month, a baked good made from leftover brewing yeast. With a thirst for trying new things, anything could be on tap.

Interested in brewing your own beer at home? Read Rose-Hamblin’s tips for homebrewing here.