How Decaf Coffee Is Made
The ill effects of caffeine have always been a concern for coffee lovers. However, it is possible to remove 99% of caffeine from coffee beans. So, how is coffee decaffeinated?
There are several ways to prepare decaf coffee. The underlying principle behind all methods is same – treating the coffee beans with some solvent that absorbs caffeine. The earliest method was invented by Ludwig Roselius. It involved steaming the green coffee beans in brine and treating them with benzene, a hydrocarbon. Due to benzene’s potential health risks, this method is eventually discarded.
In the most popular decaf method used today, coffee beans are initially steamed for about 30 minutes so that their pores open up. Then, they are rinsed continuously with either ethyl acetate or dichloromethane for nearly ten hours to remove caffeine. The remaining solvent laden with caffeine is then drained away. The beans are steamed further for another 10 hours to remove any residues of solvent. This process may be considered natural if ethyl acetate derived from various fruits and vegetables is used. But, in practise this component is artificially synthesized.
In this more recent method developed at the Max Plank Institute, carbon dioxide is used as the solvent.
Firstly, water soaked coffee beans are kept in an extraction vessel which is kept sealed. Liquid carbon dioxide is then forced into the beans at a pressure of 1,000 pound/(sq.inch). The solvent absorbs the caffeine and leaves behind flavouring components. The caffeine-filled solvent is then transferred to an absorption chamber where the pressure is released. So, the carbon dioxide returns to its original gaseous state causing it to evaporate leaving behind most of the caffeine. The gaseous carbon dioxide is now passed through charcoal to remove the remaining caffeine.
Finally, pure carbon dioxide is sent back into a pressurized container to be used on a fresh batch of beans. This method is safe as it does not involve using any chemical solvents.
Another popular method named Swiss Water Process uses water as solvent to remove caffeine. In fact, the world’s only organic certified decaffeination facility based in Burnaby, Canada is based on this method. It is solely based on solubility and osmosis.
How Much of Caffeine is Too Much?
Up to 400 mg of caffeine per day is termed as safe for healthy adults. That is the amount present in four cups of coffee. This suggests that drinking a cup of coffee in the morning may not have devastating effects on health. Decaffeinated drinks are suitable for caffeine sensitive people – those having high blood pressure, anxiety disorders, depression or cardiac diseases. People with severe coffee addiction can also benefit from decaf drinks.