With the ubiquity of craft brewers infusing coffee into their genre-blurring beers, it was only a matter of time before the inverse happened: craft roasters incorporating boozy elements into their beans. Several roasters around the country have been testing the effects of aging their coffee beans, before roasting, in former spirit or wine barrels.
Chicago’s Dark Matter Coffee is on the front line of this experimentation. Loosely inspired by knowledge of the Dutch East India Trading Company’s practice of transporting its coffee in oak barrels in the 17th century (a pragmatic move, not a sybaritic decision), Dark Matter began to play around with the concept by filling a Knob Creek bourbon barrel with El Eden beans, a company favorite variety from Mexico. When Will Eder, the roaster’s Barrel Master, pulled a sample to taste, it was wildly different from the un-barreled El Eden. “More important than being different, it was really good,” he says.
Here’s how the process works: Eder and company load raw green coffee beans into very recently-used barrels, often still damp with residual whiskey or beer. Before roasting, the beans act as de facto sponges, soaking up whatever’s left in the barrel, so moisture content is one of the major metrics that Dark Matter uses to determine the amount of time that a coffee will spend in a given barrel. The team specifically matches coffee varieties to barrels with complementary aromas: In the same way overly-woody and smoky, ashy notes in coffee are anathema to Dark Matter’s collective palate, which prefers the gentler flavors afforded by the roasting process, the same is true of charred-wood barrel flavors. The roasters seek barrel-enhancement, not barrel-domination.
Once a matured coffee has picked up the desired barrel notes and a well-integrated boozy character, the beans are dumped, roasted and bagged for limited release.
Some of Dark Matter’s biggest successes in harmonious oak maturation have been coffees aged in barrels sourced from Pipeworks Brewing Company, like one used for its The Murderous Barleywine (which, in fact, originally held Elijah Craig bourbon). The roaster has also employed barrels from culty Three Floyds Brewing Company, specifically a cognac barrel that held their coffee-infused Dark Lord Imperial Stout. One barrel the roaster used actually saw three different lives before making it to Dark Matter; it first held bourbon (Heaven Hill provenance), then Goose Island Brewery’s Bourbon County Brand Stout, followed by Goose Island’s Bourbon County Brand Barleywine. Once to the roaster, it was filled with Pacas Viejo coffee from Santa Petrona in El Salvador. When extracted from the barrel and roasted, the brewed beans packed massive, sweet fudge-forwardness, with “coffee” itself having become an almost peripheral flavor note.
The next phase of their coffee-aging program is what Eder and Aaron Campos, Dark Matter’s Director of Coffee, call “cask conditioning.” “[This] puts us in the driver’s seat, rather than at the mercy of a wood barrel,” says Eder. Here, the two are aging green coffee in a steel keg with anything from Chartreuse to complete cocktails to even brewed coffee. Whereas oak breathes and changes over time, suffusing a uniqueness in every batch, it can be wildly unpredictable. Steel is much more neutral, allowing for direct interplay between a chosen liquid and pre-roasted beans during maturation.
Coffee’s not the only caffeinated drink getting spiked by barrel-aging; tea’s in the game, too. Rodrick Markus, Master Blender and President/CEO of Rare Tea Cellar, another Chicago operation, has been delving into barrel-aging his meticulously-sourced teas for roughly a decade. “For years, we traveled to China and had our teas scented with flowers,” says Markus. He figured that if tea leaves so easily absorbed floral aromas, they could almost certainly be enhanced by time spent with the aromas waiting inside freshly-emptied barrels. Two weeks after the spirit or wine is removed, he fills barrels with tea leaves, like Chinese lapsang souchong, Indian darjeeling or South African rooibos, to name a few. Then, the barrels are spun every three or four days to agitate the leaves, ensuring more even contact with the flavor trapped inside the barrel’s walls. This aging process can take anywhere from four months to two years, depending on the tea’s saturation and flavor development.
As with Dark Matter, the key for Rare Tea is in matching leaves to aroma of the barrel. Since tea leaves are, like green coffee, sponge-like, it has been a process of trial-and-error to discover the transcendent pairings. “[We’ve had] tons of disappointments and barrels that fell apart at some time during the aging process, but [also] lots of mind-blowing combos,” says Markus. “Our Forbidden Forest lapsang souchong aged in Henry McKenna and Willett rye barrels has continued to shine every time.” Here, the base tea’s robust smokiness synthesizes beautifully with the rye barrel’s spicy and sweet notes, resulting in an umami-charged oddity neither wholly familiar as tea nor as whiskey.
These days, Eder dreams of acquiring Linie aquavit and Speyside Scotch barrels for Dark Matter, while Markus fantasizes about landing ancient port and rare sauternes barrels for Rare Tea. Let’s pray these casks somehow show up under their respective Christmas trees this year.