Tea soothes the psyche and wine makes a fellow mellow, but coffee lifts the spirits, encourages wit, and aids in the digestion of food. The coffee plant is a member of the Rubiaceae family, a large tree with dark-green waxy leaves. The fruit bears a bean called coava, a name attributed perhaps to discovery of the plant in Kaffa, an Ethiopian province. Qahwa Arabic for "coffee," or any nonalcoholic drink made from a plant, was known as the wine of Islam: The first cultivated coffee to reach Europe was called mocha (al-mulcha in Arabic), after the port city in Yemen through which coffee was shipped.
The leading producers of coffee are Brazil, Colombia, Indonesia, the Ivory Coast, and Mexico. But the taste of coffee varies from country to country, a flavor affected by the soil, the elevation of the cultivation, and the climate. The ideal soil is a rocky blend of potash, nitrogen, and phosphoric acid, a mix obtained from decomposed volcanic rock, organic matter, and mold. The finest coffee is raised in elevations of 2,000 to 7,000 feet, and the higher the altitude, the more delicate the flavor and the sharper the acidity. The perfect weather is found near the equator, a semi tropical climate with an average rainfall of 70 inches per year and a median daytime temperature of 70DF (21 DC), one where the nights are no cooler than 50DF (lODC).
Five or six years must pass before the trees bear fruit. The ovule of the fruit is called a berry or a cherry. It is a deep crimson color when ripe and about the size and shape of a cranberry. Most berries produce a pair of flat-sided beans with an ovoid shape, but occasionally they may produce a single round bean, called a peaberry, a shape that roasts evenly and promotes coffee with superior taste.
The coffee bean is enveloped in a pulpy sticky mass of mucilage that surrounds a hard, thin, beige-colored membrane called a parchment and an inner skin, known as a silverskin or an endocarp, a delicate papery texture similar to an onion skin.
Although the coffee tree grows in the wild from 15 to 30 feet, to accommodate harvest the plant is pruned to about 13 feet. The tree bears ripe and unripe fruit simultaneously. When the tree is harvested too early, the beans do not develop a full mature taste, and if they are picked too late, the brew tends to have a tainted flavor. To complete the harvest, the pickers must return to the bushes up to four times a week, a labor-intensive and costly process.
Most of the world's coffee is produced from two species of plant, arabica and robusta. The finest coffee is produced from C. arabica, a name attributed to Linnaeus, a botanist who believed the plant came from Arabia (in fact, it was brought from East Africa to Arabia in the fifteenth century). Today, arabica is cultivated primarily in Arabia (in the Republic of Yemen), Brazil, Colombia, Ethiopia, India, Mexico and, to a lesser degree, in Asia and Kenya. The arabica bean is larger than the robusta bean and produces a light-bodied brew with greater flavor. However, it is more costly to grow and harvest because it thrives in mountainous terrain, unlike robusta, which is grown on level terrain below 2,000 feet. Moreover, arabica is more delicate than robusta and more susceptible to disease.
Robusta is a hardy strain grown primarily in West Africa. The species was discovered in 1898 in the Belgian Congo by Emil Laurent. Its genus and species name is C. canephora, but robusta is named for its resistance to disease. It produces full-bodied coffee with a greater caffeine content than arabica and a more bitter taste. The bean is used as a filler in blends of instant coffee and to make commercial coffee.
The way coffee beans are processed affects taste and cost. Coffee is processed by wet or dry methods; in some regions, such as Sumatra, both techniques are used.
Arabica is processed by the wet method, a labor-intensive, costly process that is used in countries with ample moisture, for example, Costa Rica, Guatemala, Venezuela, Mexico, Kenya, and Hawaii. Fully ripe cherries are handpicked. The coffee beans are put into a tank of running water, a bath called a sluice. The inferior cherries, such as overripe or shriveled beans, float to the top along with the stems and leaves. The quality cherries sink to the bottom, and are sent to a pulping house where the gummy mucilage is removed by machine. The beans are fermented and dried. The parchment skin and silverskin are removed by a milling machine that blows off the skins as the beans come out of the tank. Next, they go to a separator machine that removes residual matter, such as sand, dust, and small or broken beans. The beans are then sorted until only the largest and best remain.
Robusta is processed by the dry method. This is the oldest and least expensive way to treat coffee; the technique is used in countries where the climate is dry and water is scarce, such as Yemen and Ethiopia. The beans are sun-dried on the tree and shaken onto cloths spread on the ground. As a result, they are exposed to the elements and the brew has an earthy flavor. The beans may also be spread in thin layers on boards and left to dry "in the husk" for 2 to 3 weeks, raked several times a day for even drying, and covered at night for protection against moisture. The beans are put in a tank where fermentation occurs without water, and the fruit is loosened from the beans. The parchment skin and silverskin are scraped off in a milling machine. The beans are then graded and shipped to roasters. The dry method promotes brew with a rich, earthy flavor, high acidity, and medium body, such as mocha from Yemen and harrar from Ethiopia.
In a natural state, coffee beans are devoid of smell and pale green, the color of hay or straw tinged with green. In the roasting process, the sugars in the coffee beans caramelize and turn brown. Short roasts produce light-brown coffee beans with high acidity and a tart taste. Long roasts result in low-acid dark-brown coffee beans with a somewhat sweeter taste.
The length of the roast influences the caffeine content. Light to medium roasts contain more caffeine than dark roasts and are served as a stimulant during the day, at breakfast or lunch. Such roasts are identified by non-European names, such as cinnamon roast and American roast. Dark roasts contain less caffeine and are taken as a digedtive following a heavy meal. These roasts have European names, such as Viennese roast and French roast.
Coffee beans contain essential oils that constitute approximately 15 percent of the beans. In the roasting process, heat draws moisture from the beans and the oils rise to the surface. It is the oils that provide the aroma and most of the complex flavor in our favorite cuppa. Because light roasts undergo a short roasting period, the oils do not rise to the surface and the beans have a dry appearance. Dark roasts undergo a longer roasting period and the surface is oily. Moreover, different roasts are blended to create unique tastes, such as Viennese, a blend of two parts medium roast and one part dark roast, or European, a blend of two-thirds dark roast and one-third medium roast.
The names of roasts vary according to the region and the roaster. To eliminate confusion regarding the appropriate roast to serve at a particular hour of the day, five roasts are presented here by color.
Light roast. A pale-brown color similar to cinnamon, a roast known in the United States as cinnamon roast, New England roast, half city roast, and institutional roast. Light roast has a tart taste with an astringent grain-like flavor and an almost sour acidity, a roast used often in blends. Because the caffeine content is high and the body is light, light roast is served as a stimulating beverage at breakfast.
Medium-brown roast. A golden brown color similar to caramel, medium brown roast is also known as American roast, brown roast, medium roast, medium-high roast, regular roast, and city roast. Medium-brown roast has a faint hint of sweetness, a well-balanced acidity, and a caffeine level appropriate as a stimulant at breakfast.
Medium-dark roast. A shade similar to milk chocolate, medium-dark roast is the acidity and caffeine content are a bit lower than medium-brown roast. Medium-dark roast is a good all-purpose coffee to serve at breakfast or lunch.
Dark-brown roast. A color similar to semisweet chocolate, dark-brown roast is also known as continental roast, European roast, French roast, and Viennese roast. The flavor is robust with a pronounced tang, a taste between sweetness and sharpness, with bittersweet overtones. The acidity and caffeine content are lower than light roast, medium roast, and medium-dark roast. Dark-brown roast is served as a digestive after a heavy meal, such as dinner.
Brownish-black roast. A color similar to bittersweet chocolate and the darkest of all roasts, brownish-black roast is also known as dark French roast, espresso roast, heavy roast, Italian roast, New Orleans roast, Spanish roast, and Turkish roast. The flavor varies from sharp to bittersweet to almost burnt, a result of a long period of carmelization. The acidity and caffeine content are the lowest of all roasts, and the flavor is the strongest. Brownish-black roast is served as a heavy-bodied brew that stimulates digestion in the late evening hours.