Training: The Coffee Plant

  • Coffee is the seed of a tropical plant of the Rubiaceae family. It grows at an altitude of between 400 and 2000 metres and at temperatures between 20.0 and 25.0C. They also need plenty of water to prosper, requiring 1500mm annually.

  • About 60 species of coffee are grown, but the most commonly used globally are the Robusta and Arabica varieties.


  • Coffea Arabica originates from Ethiopia, has a mild taste which is considered superior to the Robusta; hence it constitutes 2/3 of world production.


  • Coffea Robusta originates from Congo and was discovered in 1898. Robusta coffees have twice the caffeine content of arabicas, are more disease resistant and have a stronger flavour and heavier body.


  • Coffea Liberica  (Coffea Canephora) originates from Western Africa, but is of no great importance in the coffee trade.


  • An Arabica coffee plant can grow up to 8 metres high, but are normally trimmed to 2-4 metres when cultivated in order to gain more width.


  • Coffee trees can live for over 100 years, but are considered old and past its prime production stage at 25 years. The coffee tree can be harvested from its fifth year onwards.


  • When the coffee plant flowers, it produces a white coffee flower which has five petals and a scent resembling that of jasmine. Unfortunately this flower lasts only 2-3 days.

  • The coffee plant produces a cherry like fruit which turns from green to a bright red when it is ripe; the ripening process takes eight months. Each cherry contains two seeds covered with a thin silvery membrane; these are the coffee beans.

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  • The berries are normally harvested by hand, gathering only the ripe ones. They can also be harvested mechanically, but this means that unripe berries are picked also; producing unevenly mixed batches of the crop.


  • The berries are treated with either a dry or a wet process; both of which separate the beans form the pulp and impurities.

    The natural or dry process dries the cherries in the sun or in dryers, and the fruit is then separated from the bean by processing them through a mechanical husker.

  • The superior soaking method known as the wet process produces beans which are referred to as washed coffees.


  • The beans are then packed into standard 60Kg bags and sold all over the world.

    The typical composition of un-roasted coffee is as follows:
    Water 12%
    Nitrogenous substance 12%
    Sugar and Dextrin 10%
    Cellulose 24%
    Non-nitrogenous extractive substances 18%
    Ash 4%
    Caffettanin acid 6.7%
    Caffeine 1.2%
    Essential oils 0.1%