Botanical Traits. When grown in the tropics, coffee is a vigorous bush or small tree which usually grow to a height of 3–3.5 m (10–12 feet). Most commonly cultivated coffee species grow best at high elevations. Although they are hardy and capable of withstanding severe pruning, they are nevertheless not very tolerant of sub-freezing temperatures, and so cannot be grown in temperate climate zones. To produce a maximum yield of coffee berries/cherries (800–1400 kg per hectare), the plants need substantial amounts of water and fertilizer. Since they grow best in alkaline soils, calcium carbonate and other lime minerals are sometimes used to reduce acidity in the soil, which can occur due to run off of minerals from the soil in mountainous areas. The caffeine in coffee "beans" is a natural defense: a toxic substance which repels many creatures that would otherwise eat the seeds - as with the nicotine in tobacco leaves
Propagation and Culture.
Coffee is usually propagated by seeds. The traditional method of planting coffee is to put 20 seeds in each hole at the beginning of the rainy season; half are eliminated naturally. A more effective method of growing coffee, used in Brazil, is to raise seedlings in nurseries that are then planted outside at six to twelve months. Coffee is often intercropped with food crops, such as corn, beans, or rice during the first few years of cultivation.
In its natural environment, coffee most often grows in the shade(Paypa). However, most cultivated coffee is produced on full-sun, monocropping plantations, as are most commercial crops, in order to maximize production per unit of land. This practice is, however, detrimental to the natural environment since the natural habitats which existed prior to the establishment of the plantations are destroyed, and all non-Coffea flora and fauna are suppressed - often with chemical pesticides and herbicides. Shade-grown coffee is favored by conservationists, since it permits a much more natural, complex ecosystem to survive on the land occupied by the plantation. Also, it naturally mulches the soil it grows in, lives twice as long as sun-grown varieties, and depletes less of the soil's resources - hence less fertilizer is needed. In addition, shade-grown coffee is considered by some to be of higher quality than sun-grown varieties, as the cherries produced by the Coffea plants in the shade are not as large as commercial varieties; some believe that this smaller cherry concentrates the flavors of the cherry into the seed (bean) itself. Shade-grown coffee is also associated with environmentally friendly ecosystems that provide a wider variety and number of migratory birds than those of sun-grown coffee farms.
Processing of coffee
When the fruit is ripe, it is almost always handpicked, using either selective picking, where only the ripe fruit is removed or strip-picking, where the entire tree is shaken when most of the fruit has matured. Because a tree can have both ripe and unripe berries at the same time, one area of crop has to be picked several times, making harvesting the most labor intensive process of coffee bean production.
There are two methods of processing the coffee berries. The first method is wet processing, which is usually carried out in Central America and areas of Africa. The flesh of the berries is separated from the seeds and then the beans are fermented - soaked in water for about two days. This dissolves any pulp or sticky residue that may still be attached to the beans. The beans are then washed and dried in the sun, or, in the case of commercial manufacturers, in drying machines.
The dry processing method is cheaper and simpler, used for lower quality beans in Brazil and much of Africa. Twigs and other foreign objects are separated from the berries and the fruit is then spread out in the sun on cement or brick for 2–3 weeks, turned regularly for even drying. The dried pulp is removed from the beans afterward.
After processing has taken place, the husks are removed and the beans are roasted, which gives them their varying brown color, and they can then be sorted for bagging.