There are two main species of bean, arabica and robusta. Both thrive in equatorial regions.
Robusta is grown at lower altitudes, 0 to 700 metres, and has a high yield per plant and high caffeine content (1.7 to 4.0%). It accounts for about 30% of world production. Robusta has a stronger flavour than arabica with a full body and a woody aftertaste which is useful in creating blends and especially useful in instant coffee.
Robusta is mainly grown in the following regions:
- Western and Central Africa (Ivory Coast, Cameroon, Uganda, Angola, etc.)
- Malaysia (Vietnam, Sri Lanka, Sumatra, Java, etc.)
Arabica grows at higher altitudes, 1000 to 2000 metres, and while it has a lower yield and less caffeine content (0.8 to 1.4%) it is widely recognised to be superior to robusta. Arabica accounts for about 70% of world production, although only about 10% of this yields "grand cru" beans. Arabica has a delicate acidic flavour, a refined aroma and a caramel aftertaste.
Arabica is mainly grown in the following regions:
- Central America (Mexico, Guatemala, El Salvador, Nicaragua, Costa Rica, Panama)
- South America (Venezuela, Colombia, Ecuador, Peru, Bolivia, Paraguay, Argentina)
- Eastern Africa (Ethiopia, Kenya, Tanzania, Zambia, Mozambique)
- Papua New Guinea
Many of the cheaper blends have a higher proportion of robusta compared to arabica. Some high quality blends use a small quantity of the very best robusta beans to give body and character to the blends, particularly in espresso blends.