How is the coffee removed?

2000/10/25 Elhuyar Zientzia

• Kimika

The first method of making decaffeinated coffee was devised in 1903 by the German Ludwing Roselius. He used benzene, a very toxic solvent to extract caffeine from the grains.

At present, benzene is totally discarded and three other methods are used to make decaffeinated coffee. The first uses hot water as a solvent, but is not very specific to caffeine and removes other substances that provide flavor and smell to coffee. Using this technique, 94-96% of grain caffeine is extracted.

In the second method, methyl chloride or ethyl acetate is used to extract caffeine. The solvent is repeatedly passed through coffee beans until enough caffeine is removed and then decaffeinated grains are cleaned with water to remove traces of solvents. With methyl chloride and ethyl acetate, 96-97% of caffeine is extracted. This second method is the most used in Europe.

Finally, the third method uses carbon dioxide to remove caffeine from coffee beans. The carbon dioxide is passed to high pressure in the container where the coffee beans are found. At such high pressure carbon dioxide has special properties and becomes an excellent solvent. It is the most expensive of the three methods mentioned, but also the one that best results offers. The use of carbon dioxide allows to remove 98% of the caffeine from the grains.