Roasting Guidelines
The Decaf Roasting Challenge:
Roasting coffee for maximum flavor development on a consistent
basis is one of the greatest challenges of the coffee trade.
When
decaffeinated beans enter the roaster they do not have the
protection of internal moisture that buffers the initial exposure
to heat that they experience. Some roasters therefore recommend
starting the roast at a slightly lower temperature than you would
with non-decaffeinated beans. Further, since decaffeinated beans
are somewhat more delicate than non-decaffeinated beans, you may
find that you’ll achieve a roast color which is darker
in the whole bean than it is in the grind. The total time for a
SWISS WATER® Process roast is between 12 to 15 minutes,
depending on desired results and your roaster. Anything under that
time will produce a coffee that is all sharpness and no taste
– underdeveloped; go over that time and you want to
develop an Espresso roast.
Roasting decaffeinated coffee has often been compared to flying
blind, even by experienced roasters. The usual cues provided by
sound and sight are much less distinct with a decaf roast. When
roasting decafs you will notice that the usual two
“cracks” you hear will be much less
pronounced.
You must be more sensitive to the subtle color changes in decaf
roasts, especially going from medium to dark. Decaf coffees are all
darker in color than regular green coffee beans and the
change in color during the roast is much less distinct. In fact,
some decaf coffees won’t develop a full oily coat in a
darker roast and many inexperienced roasters will over-roast
waiting for this phase.
The Search for the Perfect Roast:
Roasting time depends on the specific origin of the bean:
-
Light Roast – Achieved about 3 minutes after first
crack, and when bean color is uniform. This roast is ideal for
coffees possessing fruitier notes such as a Costa or a Guatemalan.
However, a light-roasted Colombian, Kenyan, or Ethiopian would come
across unbalanced and too sharp, and as far as flavor development
goes – what flavor development? A light-roasted Brazil
or Sumatra would taste too much like cereal.
-
Medium Roast – About 2 minutes more than a light
roast. Works well for Colombians, Costas, Guatemalans, African, and
Indonesians. You will get a medium cup strength, noticeable body,
peak acidity, and well-rounded flavor. A medium to dark roast is
ideal for Kenyans, Sidamos, Sumatrans, and Javas – to
max out both aroma and body.
-
Dark Roast – Requires an additional 3 minutes. At
this point, turn down the heat by another quarter and wait for the
beginnings of a glossy coat on the beans. When you see this thin
sheen of gloss, take the beans off. As the beans cool, the gloss
gets reabsorbed into the beans. Any of our decafs will taste
wonderful in a dark roast, and it is recommended for folks who are
not looking for any specific origin character but rather a
non-acidic, full-bodied, sumptuous cup of coffee.
Three things will help in your quest to achieve the perfect
decaf roast:
-
Experience – Continuous practice and cupping will
give you the confidence and understanding to roast decafs well and
consistently.
-
Temperature – If your roaster doesn’t
already have a thermometer that measures the actual bean
temperature, talk to your manufacturer about having one installed.
This will help you establish parameters which you can easily
duplicate roast after roast.
-
Aroma – Check the aromatic development as often as
is practical, and compare this, roast after roast, to the final cup
and regularly record temperatures at the beginning, end and at
other definitive points in the roasting process.
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