Posted in Kafevend Blog
The first commercially
successful decaffeination process was invented by a man named Ludwig
Roselius and his co workers in 1903. The process involved steaming
green coffee beans and then using the chemical Benzene to extract the
caffeine. The use of the method was eventually halted though, as
their were health concerns regarding Benzene. However, the process of
steaming green beans and rinsing them with a caffeine absorbing
solvent survived, and is still used today.
The direct method involves
first steaming coffee beans and then repeatedly rinsing them in the
solvent ethyl acetate, each rinse reducing the caffeine content. The
beans are then steamed again to remove any residual solvent.
The indirect method involves
soaking coffee beans in hot water for several hours essentially
making an upsized coffee drink. The beans are then removed, and ethyl
acetate used to remove the caffeine contained in the water. By using
the same water over and over again, an equilibrium is established
where the beans and the water maintain a similar composition,
preventing the loss of flavours or strength in the beans.
The use of ethyl acetate is
touted as a 'natural' means to remove caffeine, as it can be derived
from certain fruits and vegetables- however, the difficulty of
actually attaining it naturally means that the ethyl acetate used is
The triglyceride process is
similar to the direct method, but instead of using ethyl acetate,
coffee beans soaked in hot water are then moved to a vessel
containing coffee oils. With this vessel heated, triglycerides in the
oils remove the caffeine from the beans. The caffeine can then be
removed from the oil and the same oil used again. This method has the
added benefit of not removing the flavours from the beans.
The CO2 process,
entertainingly known as a supercritical fluid extraction, involves
steaming coffee beans and then placing them in a high pressure
chamber with supercritical carbon dioxide- a liquid form brought on
by holding it above a certain temperature and pressure. The caffeine
is absorbed into the CO2, and can then be extracted from the CO2
using charcoal filters.
A process that boasts the
use of no chemicals whatsoever and provides 99.9% caffeine reduction
is the Swiss water process, which uses water, Green Coffee Extract or
GCE, and carbon filters. GCE is a substance made up of water
containing coffee solids without the caffeine, and like the
triglyceride process allows the transfer of caffeine from beans to it
without compromising the bean's flavours. The process involves coffee
beans being pre soaked before being introduced to the GCE and heated,
transferring the caffeine. The GCE is then passed through carbon
filters to remove the caffeine.
Despite the apparent
complexity, each process essentially boils down to heating the beans
to draw the caffeine to the surface and then repeatedly rinsing them
in a substance that removes the caffeine.
However, it is important to
know that decaffeinated coffees typically still retain a very small
percentage of caffeine, and are not really caffeine free. Luckily for
those who either try to or indeed have to avoid caffeine, in 2008 a
new species of coffee known as coffea charrieriana from Cameroon was
found to be naturally caffeine free.