How is the decaf process?

How is possible to take the caffeine off the beans? 

During many years there was just a way to drink decaf coffee.  It was instant coffee bags or jar. Luckily, now we can find decaf coffee beans to prepare it as espresso.  Now we will talk about how the process is.

Coffee beans are decaf before the roastery, when beans are still green, because at that moment the flavour is less affected

Decaf coffee is not totally exempt of caffeine and can contain a residue of 0,1%.

Various methods are used to take caffeine off the beans:

Direct contact method
In this method, the beans are in contact with decaf agents, like methylene chloride, after being prepared with water or steam.  Caffeine is taken off submerging the materials in chloride.

Indirect contact method
In this procedure, a solution of water and coffee to take caffeine off.  The solution containing the caffeine is treated with a decaf agent like ethyl acetate, and it is mixed again with the coffee beans to reabsorb the flavour.
Sometimes this method is called natural decaf because ethyl acetate is a chemical compound that is naturally in many fruits.

Water processing
This procedure is similar to the indirect method, except because there are not chemical components in it.  Coffee beans are submerge in hot water, then, the solution goes through a carbon filter to take the caffeine off.

Swiss water process
In this method the caffeine is extracted with carbon filters, but coffee beans are submerge in hot water saturated with coffee flavour.  As a result, we have the caffeine extracted without taking the coffee flavour off.
It is called swiss water process because it was created and patented by a Swiss company.

Carbon dioxide process
Coffee beans are submerged with materials softened in water, in carbon dioxide compressed.  Caffeine molecules are extracted of the beans allowing the coffee flavour molecules (that are bigger) remain unaltered.  This is the best method to retain coffee flavour.

Credits Alfred López –