Most of us do not know where coffee comes from, let alone the process that enables us to partake of this wonderful beverage. Well, coffee must undergo several steps before it can be brewed. Once in our shop we open the 132 or 154 pound sacks that reveal green, unroasted coffee beans. Once batches are weighed out, they head to the roaster.
Ours is a Diedrich IR-7 which is a gas-fired, drum machine capable of roasting small batches of beans – up to 15 pounds. The green, unroasted beans go in the hopper at the top, then dropped into the 395F rotating drum to begin the roasting process. The whole time they are roasting the beans are turning colors from green to yellow and then to different shades of brown. About 11-12 minutes into the roasting process we hear cracking noises begin. This is called “first crack” and this is moisture turning to steam and breaking through bean cell walls to escape. the temperature is approximately 380-395F. A couple minutes later we hear another set of cracking sounds (second crack) which is carbon escaping the beans. This is about the time we start checking the beans constantly to notice bean color, bean fragrance and skin development. When we think we’ve hit our mark,, we drop the beans into the cooling tray. The beans are then cooled over the next few minutes in order to stop the roasting process.
Depending on what we’re shooting for, the roasting process can take anywhere up to 18 minutes. Then we quickly cool them. What’s really happening in the roasting process is that the bean’s internal oils are being developed over the course of a carefully followed time/temperature profile. The oils are what matters- they flavor the hot water that we enjoy as coffee.