Beer on the Rocks, for a Flavor That's Boulder

White-hot rocks are shoveled into a metal basket at Dogfish Head Craft Brewery in Milton, Del.
White-hot rocks are shoveled into a metal basket at Dogfish Head Craft Brewery in Milton, Del. (Dogfish Head Craft Brewery)
  Enlarge Photo    
By Greg Kitsock
Wednesday, July 8, 2009

To come up with new beers, study old brewing techniques.

Two craft breweries on opposite sides of the country did precisely that, reviving the ancient art of stone brewing to produce two starkly different products.

Before copper and stainless steel became standard materials for brew vessels, beermakers mixed malt and hops in wooden vats. Lighting a fire under such a vessel could burn down the house, so brewers boiled the wort (the unfermented beer) by tossing in red-hot rocks, causing a partial caramelization of the malt sugars and adding smoky overtones to the beer.

Sah'tea is Sam Calagione's take on sahti, a type of Finnish home-brew. He flavored the strong ale (it measures 9 percent alcohol by volume) with juniper berries, a traditional ingredient that adds an "earthy, perfumy" flavor, and black chai tea, a nontraditional ingredient that augments the beer's citrusy character.

"It gives us a chance to look backwards and forwards at the same time and put our own off-centered spin on Old World traditions," says Calagione, president of Dogfish Head Craft Brewery in Milton, Del.

Calagione boils the wort with chunks of a volcanic rock called basalt. He heats the stones in an old wood-fired pizza oven for three hours, until they glow red and white, then shovels them into a metal basket. He uses a forklift to hoist the basket over a 15-barrel brew kettle and plunks the stones into the liquid, provoking a loud sizzle that he likens to "dropping onions into a frying pan coated with olive oil."

Finnish home-brewers, like bootleg U.S. beermakers during Prohibition, traditionally fermented their beer with baker's yeast, which according to Calagione yields a "chalky flavor and spicy, clove-y notes." But baker's yeast produces beer of varying quality, so Calagione uses a Bavarian hefeweizen yeast.

Sah'tea doesn't taste much like a hefeweizen, however. The banana flavor typical of that style isn't as dominating here. Instead, the cloudy, orange-colored brew has a rich, lip-smacking sweetness, a distinct whiff of cinnamon and a finish of citrus and clove. There is the slightest hint of phenol, although it's not clear whether that comes from the yeast or from the residue of charred oak clinging to the stones. The alcohol is well hidden.

The gray rocks, which emerge from the wort coated with a dark brown goo of crystallized sugars, are retired after a single brew, to be displayed as trophies at Calagione's Rehoboth Beach brew pub.

Calagione recommends pairing Sah'tea with highly seasoned fare such as buffalo wings or curry, noting that "the maltiness helps to tame hot, spicy foods." The beer will stand on its own as a dessert, he adds, terming it "a liquid banana bread dusted with Indian spices."

Dogfish Head isn't the first modern brewery to experiment with stone brewing. That distinction belongs to the Franz Joseph Sailer Brewery in Germany, which exported a now-defunct brand called Rauchenfels Steinbier beginning in the 1980s. Probably the first North American brewery to adopt the technique was a Tennessee-based brew pub chain called Boscos, which has been cited on National Public Radio and in USA Today for its Famous Flaming Stone Beer. About 15 years ago, a short-lived Baltimore microbrewery called Brimstone Brewing Co., nestled in the bowels of the old National Brewing plant, released a stone-brewed pale ale.

Appropriately, Stone Brewing Co., the Southern California brewery best known for its Arrogant Bastard brand, has contributed to this specialized niche, albeit indirectly. In 2006, Stone Brewing co-founder Greg Koch moved to a gleaming new brewery in Escondido, turning over the keys to his old plant in San Marcos to Tomme Arthur. Since then, Arthur's Lost Abbey line has acquired a reputation for exotic Belgian-inspired styles. Cuvee de Tomme, a barrel-aged sour ale, drew some of the longest lines at May's Savor beer and food festival in Washington.

Eager for new challenges, Arthur and colleague Tonya Cornett of Oregon's Bend Brewing Co. formulated their own version of a stein lager. Arthur heated chunks of black granite to 500 degrees over a propane burner. He made baskets by sawing the tops off several kegs and cutting holes in the sides. The kegs, filled with the glowing stones, were lowered by forklift into a vessel called a hopback, and the wort was pumped inside, spitting and crackling as it connected with red-hot rock and metal. Arthur says it raised "a big cloud of steam for 10 to 15 minutes."

The collaborative brew, dubbed Hot Rocks, combines the smooth chocolate-caramel flavor of a Munich dunkel with the heftier alcohol content (6.5 percent by volume) of a bock. Hot Rocks has the same rich, toffeelike flavor as Sah'tea, but in deference to the German purity law, it contains no spices.

A keg of Hot Rocks followed Arthur eastward to the Brickskeller here. Sadly, it will have been drained by the time this column is published. Not to worry: Arthur intends to insert his stone beer into the rotation as a spring seasonal and says he hopes to start shipping his beer to the District on a regular basis next year.

Meanwhile, Calagione says Sah'tea will available throughout the summer in 25.9-ounce bottles and the occasional keg. Look for it in better-stocked liquor outlets and at the Dogfish Head Alehouses in Gaithersburg and Falls Church; a third branch is set to open in the Greenbriar Shopping Center in Fairfax by late summer.

Greg Kitsock can be reached at

© 2009 The Washington Post Company