How many varieties of coffee are there in the world? Determining the quality starts at an early stage Before they are roasted, Arabica beans are either bluish or greenish. This difference in colour is due to the method used to shell the coffee berries. The beans are the seeds that grow inside the large berries on the bush. Each berry usually contains two beans. Just like cherries, coffee berries are ripe and ready for picking when they go from green to red. The origin influences the flavour Coffee is grown in countries situated between the Tropic of Cancer and the Tropic of Capricorn, i.e., tropical countries, where there is enough sun and enough rain for the coffee plants. We wrote above that the altitude affects the quality of the coffee. When the plantation lies at about 1800 to 2000 metres above sea-level, the coffee is called high-grown. Practically all the coffee varieties grown at such an altitude are Arabica varieties. Coffee grown below that level is called low-grown. These can be either Arabica or Robusta varieties. High-grown Arabica varieties have a mild taste, are highly aromatic, and their caffeine content is naturally low, between 0.9 and 1.5%. Compare that to tea, which contains 1 to 4% caffeine, and to kola nuts, which have a caffeine content of 2 to 3%. Low-grown Robusta coffee is rather sharp to the taste, sometimes even sour, and contains up to 2.5% caffeine. The processing of the green coffee affects the flavour Blue coffee One of the ways to get the flesh off the beans is to soak them in water and then put them through a husking machine. The coffee beans obtained by this method are bluish. Next, they are dried. This husking method gives the coffee a full and distinct aroma. In the trade jargon, these beans are described as having a 'high acidity'. This produces a pleasant sharp sensation on the palate and guarantees a long-lasting aftertaste. Experts sometimes use the word 'doré'. A clear and slightly greyish groove across the length of one side of the beans is characteristic of the best coffee varieties. Blue Arabica coffees comprise the best qualities and determine the flavour of a blend. They are grown mainly in Colombia and Central America. Green coffee Leaving the ripe coffee berries to dry in the sun first and only then putting them through a husker produces ‘green’ coffee. Because the beans are dried with the flesh on them, they have a more pervasive, tangy flavour. This processing method is mainly applied to Robusta and to Arabica varieties in dry and sunny regions (Brazil). For the best taste, the ideal blend will contain both blue and green high-grown Arabica coffee. This makes for a mild, aromatic coffee with a naturally low caffeine content. Real coffee lovers avoid Robusta and low-grown Arabicas.