Caffeine is a popular drug, one that is present in the two most popular drinks in the world (if you exclude bland old water) in coffee and tea. Tea and coffee supplies continue to be massively popular in all parts of the globe, but with the effects of caffeine too much for some there has been a rise in the decaf varieties of our favourite beverages.
The decaffeination process in coffee has been happening for well over a century, with a German coffee seller experimenting with how to remove the caffeine from his coffee beans as far back as 1903. Since then, the methods used have been developed to a point where many a coffee drinker has managed to tone down, or completely remove caffeine intake from their lives, without losing the amazing taste of their favourite blend of coffee in the morning.
Ludwig Roselius was the German coffee merchant and his process of removing caffeine from his products became known as the Roselius process, steaming the coffee beans in a brine solution and using benzene to extract the caffeine stimulant. The problem with this process was that benzene is a carcinogen, causing more problems than good, but the process was desired as a result and other, safer, methods of decaffeination have been mastered.
The most popular decaffeination process is a solvent-based one, using methylene chloride or ethyl acetate to extract the caffeine direct from the coffee bean. Coffee beans are placed in near-boiling water for hours to remove the majority of the caffeine present. Not only is caffeine removed but also oil components and flavour. The beans are removed, washed for 10 hours in a separate container where one of these solvents is present. The solvent bonds with the caffeine remaining in the beans and it is evaporated at the end of the process through a heating procedure. The beans are then placed back in the water containing the oils and flavour to absorb back in. Another process utilising these solvents is where the chemical is run through coffee beans that have been pre-steamed and evaporation takes place this way.
There are two other methods that have been taking hold in recent years with a view to refining the process so as to leave the most natural coffee taste at the end of the decaffeination process. The Swiss Water Method uses only water in its decaffeination process, running the coffee beans through superheated water. The beans are discarded after this process and the liquid containing all of the flavour is run through a filter process, leaving behind a liquid that is 99.9% caffeine free, which is used in lieu of water for a new batch of coffee beans as the caffeine is removed from those.
Lastly, a method of decaffeination is popular that uses liquid carbon dioxide through coffee beans that have been pre-moistened, circulated using 1000 pounds per square inch of pressure. Liquid CO2 becomes a highly effective solvent at this pressure, removing the caffeine from the bean, and depressurised in a separate container where the caffeine can be removed and used for other types of drinks.