In downtown Wake Forest, Matt Flinn pulls a pint of dark brown brew topped with caramel-colored foam and alive with cascading bubbles. It looks suspiciously like Guinness. Upon my first sip, however, I quickly recognize Back Alley Coffee Roasters' newest chilly beverage as, indeed, cold-brewed coffee. The brew, transformed by a nitrogen-pressurized tap, looks so similar to that iconic Irish stout that I was surprised by its earthy flavor, dominated by citrus and flower notes, not chocolate.
"The cold brew is infused with hops," Flinn says with a smile. "We're flipping the brewing script."
Flinn is referring to his recent coffee experiments with hops, inspired by collaborations with nearby White Street Brewing for coffee-infused beer. Such collaborations are frequent in the Triangle craft beer community. Raleigh Brewing Company brightens up one of its porters with Oak City Coffee Roasters' Kabum bean. Trophy Brewing's popular Slingshot Coffee Porter derives its punch from Raleigh's eponymous cold-brewed coffee. Local chocolatier Escazu roasts cacao beans for Big Boss's Big Operator black ale.
Using true craft beer lingo, Flinn and his fellow experimenters at Back Alley decided to call the beverage Citra N.H.C. (nitro hop coffee), named after the Citra variety of hops it uses. The brew's unique citrus flavors began not with hops but as a roasting accident. A Back Alley apprentice accidentally "messed up" a batch of expensive Konga beans. Instead of confessing to the mishap, he waited until the tasting crew cupped the coffee to see if anyone noticed.
"Oh, we noticed, all right," says Flinn. The apprentice lucked out when the tasting crew realized the roast perfectly matched the bright, citrusy flavor of the hops Flinn was already experimenting with.
After roasting, the coffee is ground and flash-brewed, a method using thin, precise streams of water to steep the beans. The hot coffee is then quickly chilled over ice. Back Alley uses the flash-brew method instead of the twenty-four-hour steeping it employs for its regular nitro cold-brew coffee. According to Flinn, hot water brings out the acids in the coffee beans needed to match the acidity of the hops. The nitrogen tap lends the coffee a creaminess that renders sugar and cream an unnecessary addition.
For Flinn, the Citra N.H.C. is only the beginning of his lab experiments, and not just because cold-brewed coffee makes up 50 percent of Back Alley's coffee sales. "There's no limit to the flavor profiles we can offer," says Flinn. "I can change the flavors by choosing a different bean, by grinding a different size, by using another type of water, by picking a new variety of hops, by steeping the coffee longer, and by playing around with the roasting." Flinn has already begun sampling locally grown hops for his concoctions.
"For decades, coffee hasn't changed much," Flinn adds. "No one takes risks. Incorporating beer-brewing science is just the first step. Back Alley is pouring coffee outside of the box." And, one might say, into the pint glass.
This article appeared in print with the headline "A Hoppy Accident"