Coffee Plant

The coffee tree, genus Coffea, family Rubiaceae (Madder family), is native to Ethiopia. The name coffee also refers to the fruit (beans) of the tree and to the beverage brewed from the beans. Coffee is one of the world’s most valuable agricultural crops.

There are about 30 species of Coffea, but only two provide most of the world market for coffee. Coffea arabica is indigenous to Ethiopia and was the first cultivated species of coffee tree. C. arabica provides 75% of the world’s supply of coffee. Coffea robusta, also known as Coffea canephora, was first discovered growing wild in what is now Zaire. This species was not domesticated and cultivated until the turn of the twentieth century, and now supplies about 23% of the world’s coffee. Coffea liberica is also an important source of coffee beans, but is mostly consumed locally and does not enter the world market in great quantity.

C. robusta and C. liberica were developed because of their resistance to insects and diseases.

Cultivation and harvesting

The coffee tree or shrub grows to 15–30 ft (3–9 m). The tree has shiny, dark green, simple, ovate leaves that grow opposite each other in an alternate fashion, and reach 3 in (7.5 cm) in length. Fragrant white flowers that bloom for only a few days grow where the leaves join the branches. Clusters of fruit, called cherries, follow the flowers. The cherries are green while developing and growing. The green berries change to yellow, and then to red when the cherries are mature, and deep crimson when

ripe and ready for picking. The cherries do not all ripen at once, and trees that grow in lower, hotter regions often hold multicolored berries, flowers, and leaves all at once.

Each cherry has two chambers or locules that hold two beans. The beans are oval and flat on one side with a lengthwise groove. They are covered by papery skin that must be removed before roasting. A soft, fleshy pulp surrounds the beans. Cherries with one bean, usually round, are called peaberries. Coffee trees raised from seeds generally flower the third or fourth year, and produce a good crop at five years. The trees can produce crops for about 15-20 years. Coffee trees can yield from about 1–8 lbs (0.5–3.6 kg) in a year, with 1.5–2 lbs (0.7–0.9 kg) being the average. It takes 5 lbs (2.3 kg) of cherries to produce 1 lb (0.5 kg) of beans.

Coffee grows best in regions located between the Tropic of Cancer and the Tropic of Capricorn (25°north and south of the equator), also called the “coffee

belt.” Coffee trees do not produce well in extremely hot weather, nor can they tolerate frost. Ideally, the annual mean temperature should be around 70°F (21.1°C). There should be adequate rainfall 70 inches (178 cm) per year especially when the fruit is developing. C. arabica grows best at higher altitudes 2, 000–6, 000 ft (610–1, 830 m) and because the fruit of this species takes about six to seven months to ripen after flowering, only one crop is harvested per year. C. robusta grows best at lower altitudes around 3, 000 feet (915 m), and depending on the climate and soil, the fruit can be harvested two to three times per year. Coffee trees grow best in rich, well drained, organic soil, particularly in regions with disintegrated volcanic ash. The dangers for growing coffee trees are frost, the coffee bean borer, coffee leaf miner, and the fungus Hemileia vastatrix.

There are two methods of harvesting and processing the cherries. The wet method, used where water is abundant, involves picking only the ripe cherries. The cherries are soaked in water to soften the skin and the skin and pulp are removed, leaving a sticky film. The cherries are put into tanks to ferment for about 24 hours and then washed to remove the sticky covering on the bean. The beans are spread out to dry, and put into hulling machines that remove the papery skin. Coffee beans processed by the wet method tend to be more expensive. They are considered to have a better flavor, probably because only ripe cherries are picked. The dry method involves stripping all the cherries from the branches. The cherries are thoroughly dried and put into machines that remove the dry outer covering, pulp, and papery skin. The dry method is the oldest type of processing and is currently used for about two-thirds of the world’s coffee. Both processes result in a dried, green coffee bean. Dried, processed beans are then sorted, and graded for quality, type, and size. The beans are packed for transport into bags of 132 lbs (60 kg) each. Coffee is exported all over the world and is usually roasted after it reaches its destination.

History

The first cultivated coffee, C. arabica, is native to Ethiopia. In Africa, coffee beans were consumed as food and later made into wine. The coffee plant made its way to neighboring Arabia around AD 1000, where it was made into and consumed as a beverage. coffee beans were introduced to Europe in the fifteenth century as a result of the spice trade.

Until the late part of the seventeenth century, all coffee came from Arabia, but the first coffee tree was brought to Europe by Jussieu and planted in the Jardin des Plantes, Paris, in 1714. This tree became the source of all Latin American coffees. This same tree was stolen and later replanted (after a treacherous sea voyage) in Martinique. This species spread to the West Indies and later, Brazil. The West Indian colonies of Spain and France became major world suppliers. Later, the Dutch successfully cultivated the coffee tree in Indonesia, and eventually became the leading coffee producer. When the fungus Hemileia vastatrix wiped out most of the coffee trees in Asia, the West Indian and Brazilian industry became dominant. By the late nineteenth century Brazil had vast coffee plantations and was the leading coffee producer. This status fluctuated with the emancipation of its slaves, incoming European immigrant workers, the start of many small farms, and overproduction. Today, Brazil and Colombia are the world’s leading producers of coffee beans.