“Oak enhances the flavor of coffee beans in a way that no other fuel can,” says Carlo DiRuocco of Mr. Espresso in Oakland, California. DiRuocco first learned the craft of roasting coffee and the importance of oak fuel when he was a young apprentice to a master roaster in Salerno, Italy.
Today, DiRuocco’s devotion to oak-roasted beans means a labor-intensive roasting process, but the result is coffee that’s rich and smooth without a trace of harsh acidity.
At Mr. Espresso, beans are roasted slowly, for as long as 24 minutes over a low oak fire. (Roasters typically heat their beans for a much shorter time—as little as eight minutes—at a much higher temperature.) The result is a medium-roast bean with more complexity and aroma and none of the harsh bitterness or burnt flavor of the fashionable dark roasts.