by: James Grierson

Coffee is a plant. However, before it can be drunk it must pass through a number of stages and travel thousands of miles.

Coffee beans come from the red cherries of the coffea bush. Each cherry usually contains two seeds, or coffee beans. The exception to this is the Peaberry, where only one bean is produced. The flavour a bean produces is affected by where the coffea bush is grown. Soil, climate and altitude all alter the way coffee tastes; this is why, for example, coffee from Columbia will differ in taste from region to region and from year to year.

Most coffee comes from two species of the coffea bush: Coffea arabica, simply known as ‘arabica'; and Coffea canephora var. robusta, simply known as ‘robusta'. Robusta beans are cheaper to buy then arabica beans because they produce coffee with an inferior flavour, containing more caffeine.

When the red cherries have been harvested from the coffea bush, the outer layers of pulp and skin must be removed to reveal the green coffee beans inside. There are two common methods of doing this: the ‘natural' or dry method, and the ‘washed' or wet method. The natural process of removal tends to give coffee a full-bodied yet mild aroma, whereas the washed process yields strongly aromatic coffee, with a fine body and a lively acidity.

In the washed method the outer pulp is removed using a mechanical pulping machine before the cherry is immersed into a fermentation tank for between 12 to 32 hours, after which the remaining pulp and skin is washed off, revealing the green bean. Finally, the bean is left out in a sunny area for between 12 to 15 days to dry.

In the natural method, the cherry is simply left to dry out in the sun for up to four weeks. During this time the pulp and skin become shrivelled and can then be easily removed.

The coffee beans are then sorted and graded by size and density. Generally the larger the coffee beans the better the coffee. The largest bean is known as ‘Maragogype' or Elephant bean. There is no international grading system for coffee beans, with different countries using alternative systems. For example, in many African countries, the highest grade of coffee is AA, whereas, in Indonesia it is Grade 1.

Green coffee beans must first be roasted before they can be used to make a cup of coffee. The roasting process produces the primary flavour and aroma of coffee. Beans are roasted by a skilled coffee roaster, who judges how long to roast the beans in order to produce the optimum taste. For example, Javanese coffee is usually roasted for a lengthy time to give it a full-bodied and earthy flavour. However, if heat is applied to the beans for too long, it will destroy this flavour and give it a burnt aroma.

The final process before you can enjoy your cup of coffee is grinding. The coffee beans need to be ground ready to infuse, using your preferred brewing method. Different brewing methods require a different coarseness of coffee in order to produce the best possible taste. For example, using a cafetiere you need coarse coffee grounds, whereas when using a stove-top espresso maker you require a much finer grind.