The processing is the method from which, once the harvest is finished, you get the green coffee beans ready for export.

There are three different systems:

·      Dry processing

·      Wet processing

·      Semi-washed processing

DRY PROCESSING

This is the oldest working method, used in ancient times in the Middle East by the Arabs and still used in countries like Brazil, Western Africa and South East Asia (Vietnam and Laos), where the rather dry climate during the harvest season promotes the drying of cherries.

In the dry method, cheaper and less laborious, the freshly picked fruits are spread out in thin layers and left to dry outdoors for 2–3 weeks. The exposure to the sun in the first instance, and then the action of the machine, allow the separation of the grain both from the pulp, which is now dry, and from the two protective membranes.

In this way, so-called “natural coffee” is obtained, which is uneven and characterized by a green-yellow colour for the Arabica and green-brown for the Robusta.

WET PROCESSING

This is the most widespread process in the countries of Central America (Mexico and Colombia), in Africa (Kenya and Tanzania) and in India. Developed by the Dutch in 1740, it is used in those countries where the rather rainy climate does not allow for dry processing.

Unlike the previous system, this system is more laborious and demanding, and must at the latest start the day following the harvest to avoid fermentation.

The cherries are picked by a machine that separates the exocarp from the bean. The grains obtained are then fermented in large water tanks for 1–2 days, during which a substance called “mucilage,” which covers the bean, comes away from it completely. There then follows the washing and drying phase in the sun or in mechanical dryers. The coffee obtained, which still preserves the papery and silvery film, is finally stored in well ventilated warehouses.

From this process, the so-called “washed coffee” or “mild” coffee is obtained, particularly valuable as it is very uniform in appearance: a green-blue colour for Arabica and green-yellow for Robusta.

SEMI-WASHED PROCESSING

This is a rather recent technique developed in the early 1990s, first in Costa Rica and then in other countries such as Colombia and Brazil.

Immediately after harvesting, the cherries are picked clean and partly demucilated by a machine to prevent them from fermenting. The beans are then dried in the sun or in driers in order to also eliminate the residual mucilage.

The coffee beans thus obtained are called “semi-washed.”

This system, using a smaller quantity of water than the wet method, considerably saves a resource so important in those countries.