Coffee

COFFEE, the seed (beans) of the fruits of the evergreen shrub or tree Coffea arabica L. and Coffea liberica of the genus Coffea, family Rubiaceae. The native home of the coffee tree is considered to be Abyssinia, but it is cultivated in most tropical countries. The fruit of the coffee tree in size and shape resembles a cherry; inside the fruit is a paired or single coffee bean. Good grades of Arabian coffee acquire high qualities upon storage for 3 years or more. Low grades of coffee aged for 12–15 years can also yield coffee of high quality. Commercial grades of coffee, which differ from one another in the shape and size of the beans, color, and aroma, bear the name of the localities from which they are exported (e.g., Mocha or Levantine, Javanese, Ceylonese, Brazilian, etc.). The best grade is considered to be "Mocha" coffee (Arabian). Almost all of it is consumed in its homeland, whereas in Europe, coffee with small beans exported from Java, Ceylon, and Brazil is known under the name "Mocha." Raw coffee beans possess an unpleasant astringent taste and are not consumed directly. They are roasted at 200–240° until dark brown. In the process, the water and tannin content in the coffee decreases, and aromatic substances called "caffeol" are formed. Composition of roasted coffee (in %): water 1.5–4.5; nitrogenous substances 10.8–17.8; caffeine 1.15–1.56; fat 11.0–15.0; sugar 0.5–2.0; fiber 18.0–28.0; ash 4.0–5.5; nitrogen-free extractive substances 23.0–34.0. The most important constituent of coffee is the alkaloid caffeine (trimethylxanthine C₈H₁₀N₄O₂ + H₂O). The latter is also contained in the pulp of the fruits, in the flowers, leaves, and branches of the tree, from which it is isolated in a pure form for medical purposes. Coffee as a beverage is consumed in the form of a hot water decoction; due to its caffeine content, it has a stimulating effect on the nervous system and increases the frequency and strength of heart contractions. "Caffeine-free coffee" is available on the market—a coffee preparation from which a significant portion of the caffeine has been removed. Such caffeine-free coffee has the taste and aroma of ordinary coffee, but its stimulating effect is considerably weaker. In Germany, under the name "caffeine-free coffee" (Kaffee "koffeinfrei"), there is coffee with a caffeine content not exceeding 0.08%, and under the name "low-caffeine coffee" (Kaffee "koffeinarm")—not more than 0.20% caffeine. In Eastern countries, coffee is ground into a fine powder and drunk with the grounds. In Europe, however, coffee is coarsely ground, and only the extract enters the beverage. Prolonged boiling of ground coffee with water lowers the flavor properties of the beverage because the aromatic substances evaporate in the process. Raw coffee is sometimes adulterated to improve its appearance in order to give lower grades the appearance of more valuable grades. For this purpose, coloring of the beans with turmeric, indigo, lead and copper salts, Berlin blue, etc., is used. Roasted coffee beans are sometimes glazed with sugar or molasses, which improves their appearance and increases their weight. Numerous roasted and ground surrogates are often added to ground coffee: chicory, acorns, barley, almonds, wine berries, malt, root vegetables, etc. Coffee surrogates, if they do not contain harmful impurities, are permissible for sale, but on the absolute condition that they are sold under their own name.