If Nick Kosevich tells you to chew on a quassia chip, you chew on a quassia chip. Tattooed on this guy’s right forearm is the bold outline of a cocktail strainer; on his left, a cocktail spoon. His ginger beard is big, his mustache long, his green-striped tie is tucked into a pale gray vest. “That’s, like, the most bitter ingredient,” Kosevich says of the quassia. His business partner, Ira Koplowitz (vested, buttoned down, and bearded and mustachioed, too), clarifies: “In the world.” You gnaw on the wood-chip-like bark, and you wonder whether your mouth will ever recognize sweetness again.
On a recent Saturday, Kosevich has transported most of the apothecary of Bittercube, the company he and Koplowitz, both 30, founded last year, to the Hamilton, a two-month-old Milwaukee bar where chandeliers and brocade fabrics recall the grandeur of old-world hotels. The pair trade off opening dozens of jars: There is the woodsy, stone-fruit flavor of cherry bark; there are tiny lemon-scented orbs of coriander; there are outrageously funky, smoky pods of cardamom. These spices are the foundation of the line of six types of bitters the two concoct in 25-gallon stainless-steel tanks in Madison: Cherry Bark Vanilla, Jamaican #1 and #2, Orange (finished with burnt sugar for a caramelized note), Bolivar (a light, earthy, aromatic homage to Angostura bitters, which were created by Simón Bolívar’s doctor, hence the name) and Blackstrap (molasses).
Kosevich and Koplowitz, who are close friends, left their cocktail lounges (Town Talk Diner in Minneapolis and Chicago’s the Violet Hour, respectively) in 2009 to open their own craft-cocktail bar in Milwaukee. But a few months after they made the move, they realized their vision differed from their main investor’s, and they dropped the project. “We had moved our lives to new cities to do this, and then we kind of had to regroup and figure out: What are we gonna do?” Koplowitz recalls. “[We weren’t] gonna put our tails between our legs and crawl back to where we were…. So we harnessed that energy into the consulting side of the business.”
The duo began developing Bittercube bitters while maintaining a six-month “residency” in which they created the drinks, bartended and trained the staff at Milwaukee restaurant Bacchus. The bitters are now sold retail in Georgia, Minnesota, New York, Illinois and Wisconsin.
“Getting new distribution is scary in the sense that we run out of product, because [the bitters] take so long to make,” Koplowitz says. The process of making bitters stretches over months and is not especially glamorous: They use no extracts or oils, so a large batch begins with the delivery of a pallet of citrus—and some assistance from friends. (“They think that they’re gonna learn how to make bitters, but really they’re just gonna peel grapefruit for ten hours,” Kosevich says.) The spices, barks and roots macerate for weeks in a spirit; for instance, Koplowitz and Kosevich use three-year-aged high-proof whiskey from Madison’s Yahara Bay distillery for this step in the Cherry Bark Vanilla–making process. The duo feel strongly about combining the flavors early on: “If you were to make a tincture of gentian and a tincture of quassia and then put them together, it does something,” Koplowitz explains. “But if you take quassia and gentian together, in a neutral-grain spirit or a high-proof whiskey, then it does something altogether different.” (Oh, yeah, quassia and gentian? They’re bitter plants.)
When they’re not testing out new batches of bitters—barrel-aged blood orange is in the works—the pair work events and take on new clients, developing drinks to fit the needs of bars and restaurants. Take the Hamilton: It stocks Bittercube’s bitters, its menu consists of cocktails created by Koplowitz and Kosevich to match the bar’s aesthetic (such as the Drake, a riff on a French 75 in which cognac and Benedictine are topped off with sparkling wine and a few drops of Bolivar bitters) and, one night a week, the guys tend bar. The duo’s reach extends to Chicago, where they’ve consulted at the Charleston, designed a new drink menu with the Whistler’s Paul McGee for Chizakaya and, most recently, have worked with the soon-to-open Union Sushi + Barbeque Bar to create cocktails that complement the izakaya’s menu.
“With creating Bittercube we realized, like, maybe we can effect change on a larger scale, instead of putting our feet in cement [in one bar] here in Milwaukee,” Kosevich says. “We really focus on enabling the people we train. We want to teach people to do what we do.” Except, that is, for one thing: Bitters recipes traditionally are kept close to the vest; so as for how exactly their bitters are made, Kosevich says that’s staying between him, Koplowitz and their laptops.
Sip Koplowitz and Kosevich’s cocktails at Chizakaya and Union. Bittercube bitters are sold at Lush Wine & Spirits and at bittercube.com.