There are two main methods of processing which is known as wet and dry processing.

Wet Processing

In wet method processing, the coffee beans are washed or soaked in water to remove the outer pulp before drying. First, the freshly harvested cherries are passed through a pulping machine where the skin and pulp is separated from the bean. The pulp is washed away with water, usually to be dried and used as mulch. The beans are separated by weight as they are conveyed through water channels, the lighter beans floating to the top, while the heavier, ripe beans sink to the bottom.

Secondly, the beans are transported to large, water-filled fermentation tanks. Depending on a combination of factors -- such as the condition of the beans, the climate and the altitude -- they will remain in these tanks for anywhere from 12 to 48 hours. The purpose of this process is to remove the slick layer of mucilage the parchment; while resting in the tanks, naturally occurring enzymes will cause this layer to dissolve. When fermentation is complete the beans will feel rough, rather than slick, to the touch.  At that precise moment, the beans are rinsed by being sent through additional water channels. They are then ready for drying.
The coffee has to be dried for several days to lower the moisture content.  It is laid out on patios for 7-8 days where it is turned and raked 8 times a day. 

Dry Processing

Dry process, also known as unwashed or natural coffee, is the oldest method of processing coffee. The coffee cherries after harvest is first cleaned and then placed in the sun to dry on tables or in thin layers on patios. Depending on the weather, this process might continue for several weeks for each batch of coffee. Until the cherries reach a moisture level, we rake the cherries frequently during drying.