Pop, Pop

Roasting is where coffee's flavor is fulfilled. The green coffee beans are heated in large, rotating drums using temperatures of about 550 F (288 C). The tumbling motion of the drums keeps the beans from burning.

Photo courtesy Kona Coffee/Bay View Farm Coffees Roasters take the raw, green coffee beans and turn them into the aromatic beans you find in the coffee shop.

The beans first turn a yellowish color and smell a little like popcorn. After about 8 minutes, the beans "pop" and double in size. The beans have then reached about 400 F (204 C) and begin to brown as the oils within them start to emerge. This oil is called coffee essence or caffeol. The chemical reaction of the heat and coffee essence is called pyrolysis, and is what produces the flavor and aroma of coffee. A second "pop" occurs about three to five minutes later and signals that the bean is fully roasted.

Photo courtesy CoffeeResearch.org Before and After: Green (left) and roasted coffee beans (right)

Roasting Time Roasting times vary depending on the type of coffee you want: 7 minutes - lightly roasted; typical American mass-marketed coffee 9 to 11 minutes - medium roast; a full-bodied roast that is sometimes called "city roast" 12 to 13 minutes - dark roast; known as French or Viennese coffee; like the specialty coffees of the Pacific Northwest 14 minutes - darkest roast; known as espresso roast (The beans actually begin to smoke, and the sugars in the beans caramelize and burn.)

Coffee roasting is something of an art. Roastmasters use sound, sight and smell to determine when the beans are roasted to perfection. Timing is everything. Roasting time affects the color and flavor of the final brew, so the length of the roasting period depends on the type of coffee desired (shorter for American brew, longer for espresso).