The seed of Caffea Arabica; café, Fr.; Kaffee, Ger.

Composition

Coffee contains an alkaloid — caffeine — which is nearly, if not quite, identical with theine, a principle found in tea; a volatile oil; a form of tannic acid; sugar, gum, etc. The tannic acid is that variety known as caffeo-tannic, or caffeic.

The peculiar odor and flavor of roasted coffee are due to the caffeic acid, which is, in part, converted into methylamine; to the aromatic oil; doubtless, also, to the sugar, which is changed into caramel.

Preparations

Coffee is never used in the raw state as a beverage. After roasting, it is made into an infusion or decoction. An infusion made at a low temperature, which should not exceed 200° Fahr., is better than a decoction. If the heat be too great, those aromatic constituents which impart to coffee its special aroma, are dissipated. Coffee is now usually prepared by the process of percolation. The best product is obtained by steeping the coffee for some time in hot water. Coffee can be "settled," or clarified, by the addition of some white of egg, or isinglass, or by pouring on from a height some cold water.