Use these Seven Steps as our guide to help improve your decaf
roasting
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Cupping
The fundamental practice of cupping coffees and pulling
shots of espresso will always be the final arbiter in deciding the
best roast profile and/or methodology. Let the coffee itself tell
you what roast is best for it.
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Full Batches
Roasting full batches, or as close to full as possible,
will reduce potential tipping, scorching and uneven bean
development as SWISS WATER® Process decaf beans tend to
be more sensitive to heat than regular beans.
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Time of Day – Impact on the Roast
We suggest roasting SWISS WATER® Process decaf
as part of the end of the roasting schedule as the roaster is
moving in the cool down direction. This allows the roast to develop
with the aid of the radiant heat from the roasting equipment,
resulting in less time that the beans are in the roast chamber and
less energy needed to develop the roast.
Commonly decaf coffees are scheduled for the first roasts of the
day when the roaster is cold. The logic is that less heat will be
directed into the roasting bean mass, since the drum is drawing
much of this heat away as it warms, allowing for a longer and
gentler bean development. As a result, what tends to happen with
this approach is that beans spend an unnaturally prolonged time in
the roast chamber with more heat and airflow stripping away the
beans’ positive flavor qualities.
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Charge Temperature (Drum Roaster)
Once the roaster has reached operating temperature, use a lower
charge temperature – anywhere between 25º -
35º F lower (14°- 20° C) than what
is used for roasting regular beans.
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Adjusting Airflow
Experiment with airflow (depending on the roasting
equipment’s control factors of airflow into or out of
the roast chamber) as a tool for controlling bean development rate
and ensuring an even roast with the best resulting cup quality. The
sensitivity of decaffeinated coffee beans makes them susceptible to
having their positive cup qualities/flavor stripped away when too
much time is spent in the roast chamber under higher airflows, due
to the efficiency of convection heat transfer.
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Roast Development
Once first crack is underway and wisps of smoke can be
seen emanating from the beans in the tryer begin gently reducing
the heat input of the roaster. This will create sufficient time
between 1st and 2nd crack, which is critical for the development of
positive cup characteristics. However, this also creates the danger
of stalling the roast – a drop in roast chamber
temperature – if the heat input is reduced too much or
too quickly.
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Visual Cues
Checking the beans with the tryer during the roast is
always an important practice when roasting any coffee bean. As
SWISS WATER® Process decaf beans are already slightly
darker green before the roast begins, the roaster-operator needs to
pay very close attention to bean development with the aid of the
tryer while listening for first and second crack to guide their
adjustments.
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Cupping
Cup it! And confirm you will be giving your customers the
highest quality coffee experience.
