Coffee

Coffee as a drink, usually served hot, is prepared from the roasted seeds (beans) of the coffee plant. Due to its popularity, coffee is the second largest traded commodity in terms of dollar value in the world (after oil). It is one of mankind's chief sources of the stimulant caffeine. Because of this, coffee's nutritional benefits are disputed, sometimes labeled a cure-all, other times labeled a health hazard (see caffeinism).

Coffee can be brewed in several different ways, but these methods fall into four main groups depending upon how the water is introduced to the coffee grounds. If the method allows the water to pass only once through the grounds, the resulting brew will contain mainly the more soluble components (including caffeine), whereas if the water is repeatedly cycled through the beans (as with the common percolator), the brew will contain more of the relatively less soluble compounds found in the bean; as these tend to be more bitter; that type of process is less favored by coffee aficionados.

Coffee in all these forms is made with coffee grounds (coffee beans that have been roasted and ground) and hot water, the grounds either remaining behind or being filtered out of the cup or jug after the main soluble compounds have been removed. The fineness of the grinding required differs by the method of intended drink production.

Water temperature is crucial to the proper extraction of flavor from the ground coffee. The recommended brewing temperature of coffee is 93 :C (204 :F). Any cooler, and some of the aromatics that make up the flavor will not be released. If the water is hotter, some undesirable elements will be pulled from the grounds, affecting the taste.