Roasting transforms green coffee into the aromatic brown beans that we purchase in our favorite stores or cafés. Most roasting machines maintain a temperature of about 550 degrees Fahrenheit. The beans are kept moving throughout the entire process to keep them from burning. When they reach an internal temperature of about 400 degrees Fahrenheit, they begin to turn brown and the caffeol, a fragrant oil locked inside the beans, begins to emerge. This process called pyrolysis is at the heart of roasting — it produces the flavor and aroma of the coffee we drink.
After roasting, the beans are immediately cooled either by air or water. Roasting is generally performed in the importing countries because freshly roasted beans must reach the consumer as quickly as possible.