Coffee Bean Categories and Decaffeinating Methods
There are three major categories of coffee beans, milds, Brazils, and robustas. Coffea Arabica is the tree that the milds and Brazils come from. This tree best grows in a high elevation with plenty of water. The minimum elevation this tree normally grows at is 2000 feet above sea level and the highest 9000 feet above sea level. Of the milds and Brazils the milds are considered superior to the Brazils. The Brazils do not necessarily always come from Brazil but they usually do, they can come from Africa or the Pacific as well. The milds come from a higher elevation from various countries usually 4000-8000 feet above sea level and they are more carefully picked at the proper time and dried in a more careful fashion than Brazils. The third category the Robusta comes from the Coffea canephora var, robusta tree. This coffee is considered the lowest grade. It is very hardy and resists disease, temperature changes, and can grow at lower elevations than the Arabica. Robustas have from 40% to 100% more caffeine than arabica. Three major aspects are given to coffee grading is, size of the bean, the type (mild, Brazil, or robusta), and preparation method given earlier. Pea berries are two beans that have grown together as one and are considered to have a more delicate flavor. For decaffeinated beans one of three basic methods are used. The direct, indirect, and swiss water method. The indirect method utilizes soaking the beans in hot water. This pulls out most of the caffeine from the bean which goes into the water. The water is then treated with a solvent to neutralize the caffeine. The water also has a lot of the bean flavor in it also that was leeched out during the soak. After the caffeine is neutralized in the water the water is then sprayed back onto the beans with the flavor giving back most of what the bean lost. This is done after the solvent is removed by filtering. With the direct method, beans are soaked in the chemical solvent right away, the solvent is not added later as in the indirect method. The solvent is then filtered out then the water with the bean flavor is sprayed back onto the beans. Methylene Chloride (DCM) is usually the solvent that is used. During roasting virtually all of the solvent is removed that was left that did not get filtered out. Another solvent that is used is Ethyl Acetate which is used when a more natural method is desired because it is derived from fruit in nature. Industry makes it with acetic acid and ethyl alcohol for decaffeinating use. Carbon dioxide gas (Co2) which is naturally occurring in the air we breath is considered a very natural solvent. The Carbon dioxide is pressurized into a liquid then the liquid absorbs the caffeine. Charcoal filters remove the caffeine from the carbon dioxide. Swiss water method uses a water soak without a solvent similar to the indirect method. The water absorbs the bean flavor and the caffeine. The caffeine is then removed with charcoal filters which only remove the caffeine. A new batch of beans is brought in that are put into the bean flavored water with the caffeine removed. The caffeine from the new batch goes into the water and then the bean flavor in the water goes into the bean. The reason the flavor does not come out of the bean is the water is fully saturated with bean flavor from the first batch and no more can go into it thus the flavor that was in the bean stays in it. The caffeine can come out because of the different chemical structure from the flavoring. All types of beans including decaffeinated are available here at Coffee For Less By Glenn Heitkoetter - |