Roasting

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 undergoes
several steps before it reaches us.  Once in our shop we open the 132 or 154
pound sacks that reveal green coffee.This means it's still unroasted. That's where
our machine comes into play.  Ours is a Diedrich IR-7 which is a gas-fired, drum
machine capable of roasting small batches of green - up to 12 pounds.  The short of it is that the green goes in the hopper at the top, then into the rotating drum at about
360 F.  Several minutes pass as we adjust gas pressure and air flow. The
whole time the beans are turning colors from green to yellow and then to different
shades of brown.  Then about 11-12 minutes into it, we hear cracking noises.
This is bean moisture which must escape the beans at about 380-395F.
 A couple minutes later we hear another set of cracking sounds. This is carbon
escaping the beans. This is about the time we're checking the beans every
five seconds to check bean color, smell and skin development.  When
we think we've hit our mark- usually about 435+F for a medium coffee, 460+F
for light to medium French, we dump the beans into a 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 usually takes anywhere from 14 1/2 to 17 minutes besides the cooling
time. What's really happening in the roasting process is that flavor oils are being
developed over the course of a carefully followed time/temperature profile.  
The oils are what flavors the hot water that we enjoy as coffee.