Coffee is a delicious and wholly natural product
that contains several hundred different chemicals and that help to
define its distinctive taste and aroma.
Caffeine is just one of these naturally occurring substances. It
is an extremely difficult process therefore to remove only the
caffeine and leave the other chemicals intact. To all intents and
purposes this is an impossible task and even the best and most
carefully produced decaffeinated coffees will have its taste and
aroma altered by the decaffeinating process.
Coffee comes in two major varieties: Arabica coffees and Robusta
coffees. The Robustas typically contain twice the amount of
naturally occurring caffeine as the Arabicas.
So how do manufacturers go about removing the caffeine from the
bean?
There are several different methods in use today, all of which
treat the green or raw coffee bean before roasting.
A popular method is known as “Water Processing”
that was originally developed by the Swiss in the 1930’s.
This process involves soaking the green coffee beans in hot water
to extract all the soluble and semi soluble compounds (including
the caffeine) into the solution. The first batch of ‘used’ coffee
beans are then removed and thrown away. The solution containing all
the coffee compounds is then treated to remove the caffeine by
passing through carbon filters in solution. These carbon filters
are designed to only remove the caffeine molecules and to allow the
other compounds in solution to pass through.
A new batch of raw coffee beans is now introduced into the
‘filtered solution’ which has been kept at the same temperature
throughout the process. The ‘clever’ part of this process is that
since the hot water solution has reached equilibrium and already
has the maximum amount of coffee compounds suspended in solution,
then when the new beans are introduced only the caffeine is
dissolved out from the new beans and the other compounds remain in
the bean as they are unable to be extracted by the hot solution
that already contains them from the original batch!
The beans are then removed, dried and sent away for roasting.
This process is repeated many times using the original solution,
which is continually treated to remove the caffeine.
Other processes used to remove caffeine rely on similar
principles as water processing but use different ways to soak the
beans and different ways to extract the caffeine. For example some
processes use steam instead of soaking the beans and use solvents
to remove the caffeine. Others use carbon dioxide and oxygen gases
to achieve a similar thing.
It should be noted that there are different criteria for
labelling coffee as decaffeinated: The International Standard
demands 97% of the caffeine to have been removed from the beans and
the European EU Standard of having 99.9% of the caffeine removed by
mass.
Written by Fenton Wayne - (Fenton Wayne is an independent advisor
in the coffee and vending trade where he has over 25 years
experience. This article has been submitted to and distributed
by www.submityourarticle.com)