Tucked away inside the experimental Jamaica Plain brewery of The Boston Beer Co. is a room you can smell as soon as you crack open the sliding door. Samuel Adams doesn't brew much of its beer in Boston anymore. But a national craft brewery with Boston roots keeps a funky secret inside its walls here.
Samuel Adams founder Jim Koch is proud of his barrel room. On a tour of the space earlier this year, Koch introduced me to something called Kosmic Mother Funk or "KMF", a blend of yeast and bacteria used in Sam's Barrel Room Collection beers. A secondary fermentation with Brettanomyces yeast helps turn malt and hops and water into a sour, funky substance. That sour beer is then imparted into the five Samuel Adams Barrel Room Collection brews.
Samuel Adams started the series with three beers -- New World Tripel, American Kriek and Stony Brook Red -- in 2009. They introduced a fourth beer, Thirteenth Hour Stout, and last month debuted a fifth, called Tetravis.
Tetravis is a Belgian Quadrupel style beer. It's typically strong, lugging with it a 10.2 percent ABV. It is decidedly a cold-weather beer, which seems appropriate as we transition between seasons. Opening up a bottle on a nice summer day seemed out of place, but there are sacrifices to every job. When I popped the cork a wasp fluttered toward the mouth of the bottle, attracted to the smell wafting from the opening.
The beer pours a cloudy brown. Candied sugar and fruitcake form a welcoming nose, like the scent from a warm oven on a cold morning. As expected the first sip is very sweet, a mashup of plums and baked bread and caramel. This sweetness is cut, however, by a welcoming acidic bite from the KMF. Quads are heavy, but this one is a few degrees lighter. That bit of levity has brought me back to Sam's Barrel Room beers quite a few times.
Koch is proud of the balance the beers in the series show.
"You've got to get the KMF to the point of being borderline pleasant," he says. "I don't want to release a beer unless it's a pleasure to drink. Even if it's weird."