13
Just as you are entering first crack there is a chemical reaction going on in the beans called the Maillard
Reaction. Chemical changes in the beans are actually creating heat- the beans are becoming exothermic.
The sounds of first crack begins with a sound reminiscent of breaking small wooden sticks. It begins with
a few clicks and then increases in frequency. As first crack becomes more active, the heating element
should have already been turned down to around 50% (
13
). Depending on how things are going you may
need to turn the fan up as well (
14
).
Another change you will notice is that the beans are expanding. That is where the sounds of first crack
come from. You will observe that the level of the beans in the roasting chamber has risen against the glass.
They expand so much that they emit that distinct cracking sound.
The roast is nearing completion, and you are just minutes away from ejecting the beans. First Crack is
about to end at about an indicated 400 F. If you have done well up to this point, from the end of first crack
to the beginning of second crack you should have a pause of about two minutes (
15
). The exact length
of time does not have to be precise, but if you get about 1:30 to 2:00 minutes lull time between those two
periods you are doing a pretty good job.
As you can see, this roast progressed a little too quickly and the heating element should have been
turned down a little earlier and down to about 30% by the 13:30 time mark. This example is offered be-
cause it is important for you to realize that you shouldn’t hesitate to make adjustments other than those
specifically described in this section. The goal of this section is only to give you a better understanding of
what is happening so you can learn to control the process. Much like trying to write an article on how to
fry an egg, it is easy to tell someone to raise the pan to control the temperature of the pan as well as what
to watch for, but difficult to tell them exactly how high to raise the pan on the burner— knowing that takes
experience.
Notice again that even though you have turned the heating element’s power down to half, the tem-
perature continues to rise. Listening carefully and you will begin to hear the first few clicks of second
crack. These sound like breaking toothpicks (
16
). It will start just like first crack, with a few stray clicks,
and then turn to a rapid series of those same sounds. If the number of these clicks per minute decreases
be wary! This is the time when coffee is becoming so dark that it can lose a lot of its flavor. When the
beans look oily or greasy, five seconds is a long time in the life of a roasting coffee bean. Even though the
graph line of the display temperature is now beginning to flatten, the bean temperature continues to rise
as second crack progresses.
This is the time you need to decide when to hit the eject button to end the roast. But when? There is no
one answer. When to end the roast depends on the coffee you are roasting and how it will be brewed, and
most importantly, your preferred taste. For Colombian coffee brewed as drip, I would recommend trying
a lighter roast than you may be accustomed to. Maybe hit eject just before second crack begins, or maybe
even predict second and eject the beans a minute before second crack starts. For an espresso blend, try
ejecting about ten seconds after second crack becomes active.
Over time, if you experiment with various roast levels you will be surprised at how the taste changes
depending on the various changes you make during the roast. Experiment! Don’t be afraid to try some
lighter roasted coffee. Try to vary the drying time. Try shorter or longer time periods between first and
second. Each of these changes will change the taste of the coffee- sometimes for the better, sometimes
not.
Be aware that as a general rule, the lighter the roast, the more the coffee benefits from a post-roast
rest period before first use. Some coffees actually benefit from a ten day rest, but about two to four days is
usually sufficient for most coffee.
Roasting coffee is part science and part art. We hope this section gave you a better understanding so
that , over time, you can use this scientific knowledge to become a coffee roasting artist.
