Dark roasted coffees are dark brown in color, like chocolate, or sometimes almost black. They have a sheen of oil on the surface, which is usually evident in the cup when the dark roast coffee is brewed. The coffee’s origin flavors are eclipsed by the flavors of the roasting process. The coffee will generally have a bitter and smoky or even burnt taste. The amount of caffeine is substantially decreased.
To reach the level of a dark roast, coffee beans are roasted to an internal temperature of 240°C (464°F) — about the end of the second crack — or beyond. They are seldom roasted to a temperature exceeding 250°C (482°F), at which point the body of the beans is thin and the taste is characterized by flavors of tar and charcoal.