Decaffeination
Coffee Decaffeination Process
Decaffeinating coffee is
achieved through a variety of decaffeination
processes, all of which are relatively harmless
to your health, but harmful to coffee quality. Almost every process for decaffeination
consists of soaking the beans in water to dissolve
the caffeine, extracting the caffeine with either
a solvent or activated carbon, and then re-soaking
the coffee beans in the decaffeinated water to
reabsorb the flavor compounds that were lost in
the initial extraction. The solvents typically
used are methylene chloride or ethyl acetate, which
both have a low boiling point. Since ethyl
acetate is found naturally in fruits you will hear
people call this process "natural." In any
case the solvent never comes in contact with the
coffee bean itself, but only the water solution
containing the caffeine that was previously extracted
from the coffee bean. Therefore the water
decaffeination process is relatively benign. All
methods used to decaffeinate coffee are based on
equilibrium principles and solvent/solute properties. As
such, neither all of the caffeine is removed from
the coffee, nor are all of the flavor compounds
returned or left in the coffee. The chemical
composition of decaffeinated coffee (or decaf coffee)
is altered, and therefore the flavor and aroma
are changed.
How to Decaffeinate Coffee
Swiss Water Process
In the Swiss Water Process,
the green coffee beans are soaked in hot water
to remove the caffeine and compounds responsible
for much of the flavor of the coffee flavor. The first batch of
coffee beans is then discarded, while the caffeine
is stripped from the solution by means of activated
carbon filters. This leaves a solution saturated
with flavor compounds, which is then used to soak
a new batch of decaffeinated green coffee beans. The
principle of water procesed decaf coffee is that
the solution is saturated with all components soluble
in water other than caffeine. Therefore, only the
caffeine in the bean is allowed to escape whereas
the rest of the compounds are in equilibrium. Unfortunately,
the flavor of batches is intermixed since the chemically
saturated solution is used repeatedly.
CO2 Process
In the carbon dioxide decaffeination
process, green coffee beans are soaked in highly
compressed CO2, which extracts the caffeine. The
caffeine is then removed from the CO2 using activated
carbon filters, which are then reused to extract
caffeine from the coffee again.
Sparkling Water Process
The sparkling water decaffeination
process is similar to the CO2 method, but instead
of removing the caffeine with activated carbon
filters, the caffeine is washed from the CO2
with sparkling water in a secondary tank, which
is then recycled to extract more caffeine from
the coffee. The
solvent consists of approximately 99.7% compressed
carbon dioxide and 0.3% water.
Back
to Our Coffee |
