Decaffeinated coffee has long been in demand as many people enjoy the taste of coffee, but either can’t or shouldn’t ingest caffeine. There are several processes that can remove the caffeine from coffee. Most today use water decaffeination because it is considered to be the healthiest process.
One of the earliest methods to produce decaffeinated coffee resulted in the coffee brand Sanka. This method, which steams the coffee in brine and then applies benzene to the beans, is now considered highly unsafe. Benzene is a dangerous chemical with one of its other application being its use in early Napalm. Sanka no longer uses this method.
The direct method steams the beans for half an hour and then rinses the coffee beans with ethyl acetate or methylene chloride. After the chemicals are drained, the beans are then steamed again. When this process uses ethyl acetate derived from fruit or vegetables, the coffee is said to be naturally decaffeinated.
Instead of steaming the coffee beans, the water method or the indirect method soaks the beans in water. The water is then drained and either ethyl acetate or methylene chloride is added. These chemicals evaporate as the beans undergo intense heat. The beans then take another bath in water that is reused because it is thought to contain the essential flavor and oils of the coffee. This indirect method is often thought preferable, though coffee enthusiasts argue that the process compromises taste.
A variant of the water method employs a charcoal filter instead of chemicals to produce decaffeinated coffee. The charcoal is normally coated with a carbohydrate solvent, as well as water. This is thought to prevent the charcoal from absorbing not only the caffeine but also the flavor of the coffee.
The carbon dioxide method is thought to be the most effective. The beans are steamed and then soaked in carbonated water. The water is then drained through a charcoal filter. One final process soaks green coffee beans in a water and coffee solution to remove the caffeine.
Many natural food stores now boast naturally decaffeinated coffees that use either the water or charcoal method. For those who must completely avoid caffeine, it is important to note that decaffeinated coffee contains a residual amount of caffeine. Caffeine is about 97% reduced by decaffeination processes, but the coffee is not completely caffeine-free.