The classic coffee-growing regions are in tropical Central and South America, tropical Africa, and India and Indonesia in Asia. The plant genus Coffea comprises more than 60 species. The coffee trees are bushes or small trees up to 2 m high, which bear their flowers in the axils of opposite leaves. The white flowers emit a pleasant fragrance.
Coffee has been planted only since the 13th century. The country of origin of coffee production was Yemen. In the 16th century, Moka in what is now Yemen was the most important coffee center.
The seedlings of the coffee tree are nurtured in a nursery until they are about 10 cm high. Then the seedlings are repotted for the first time. When the coffee tree seedlings have reached a height of 40 to 50 cm, they are taken to the planatage and planted in the ground under shade trees. After 3 to 4 years the first flowers appear on the tree, which in 8 to 10 months mature from green to red coffee cherry.
In each coffee cherry there are 2 coffee beans. The ripe coffee cherries are picked individually by hand during the harvest, which takes about a year.
The structure of a coffee bean
In dry processing, the coffee cherries are laid out on drying stations. For two to three weeks, they are pushed back and forth there with rake-like equipment until they are dried. When the pulp is completely dry, the coffee beans are broken up in crushing machines and freed from the dried pulp, the parchment cover (parchment) and the silverskin. Use:
- break open
The washed coffee has a higher quality than the unwashed coffee. Washed coffee has a fine, aromatic flavor. The beans have a bright, almost whitish notch. The unwashed coffee is tart and strong in taste. Its beans have a dark notch. The term washed coffee simply means that the coffee has been processed wet. The process does not serve to clean the coffee. The coffee cherries are placed in swelling tanks, where during the night the pulp swells and then the majority is removed by machine. The coffee beans processed in this way are still surrounded by a silver skin, a glassine layer and pulp residues. They are taken to a fermentation tank for fermentation, where the pulp residues ferment and the glassine layer gradually separates from the beans. The fermentation process refines the flavor of the coffee beans and takes about 1 to 2 days. The fermented beans are then washed scrupulously clean and then taken to the drying area. The beans are dried in the sun by turning them once every hour. A hulling machine finally removes the parchment cover as well as the silver skin from the coffee bean. The green coffee is now finished and can be bagged. Only particularly high-quality coffees are additionally polished, cleaned and sorted by hand. Use:
- remove pulp
The green coffee is sold in 60-70 kg bags.
During roasting, the raw coffee beans are heated in roasting ovens for 10 to 15 minutes to a temperature of up to 200°C and then cooled in cooling drums. Cooling stops the roasting process.
Each type of coffee requires a different treatment. The quality of the green coffee delivered varies from year to year.
The weather conditions in the country of origin during the growing and harvesting phases have a great influence on the coffee quality. It is up to the experience of the roast master to produce a high quality coffee ready for the market by controlling the roasting processes. There are different roasting levels: light, medium and dark roasting.
Three types of coffee are produced worldwide:
The coffee variety originates from the highlands of Ethiopia, where it is grown at altitudes between 1,300 and 2,000 meters. The "Arabica" variety is grown in all coffee-producing countries except those in West Africa and Madagascar, and in Indonesia. "Arabica" only thrives in warm, tropical climates and requires a lot of rainfall. Arabica coffee does not tolerate large temperature fluctuations. Despite having little caffeine, this variety is highly appreciated for its pleasant aroma. "Arabica" is the most widely grown coffee variety.
This type of coffee includes many local varieties. For world trade, the "Robusta" variety is the most important. "Robusta" coffee is more resistant and higher-yielding than "Arabica". The variety is native mainly to the tropical jungles of Africa. The plant likes to have about 1,400 mm of annual rainfall spread over 8 months. The fruits are larger than those of "Arabica". "Robusta" is planted in West Africa as far as Uganda, in Madagascar and in Indonesia. This variety has permanent foliage.
This type of coffee is grown in Liberia and the Ivory Coast. The "Liberica" coffee tree grows larger than the trees of all other coffee varieties. The fruits are also larger. This type of coffee is not very popular and therefore is not grown much anymore.
The "Arabica" coffee has a fine aromatic taste. It is roasted light to medium. It is mainly enjoyed as coffee crème and as black coffee.
Robusta" coffee has a tart and strong taste. It is roasted medium to dark. It is mainly enjoyed as espresso and ristretto.