The coffee bean extraction and drying processes create different characteristics in the end product.
Wet / Washed is where the various layers of skin and fruit around the bean are stripped off gently and gradually, layer by layer, before the bean is dried. The resulting cup is more consistent, cleaner, brighter and acidic.
Coffee can be "extra" washed by soaking the coffee a second time after the mucilage has been removed. This can prolong the coffee's shelf life and improve the quality of the coffee.
Dry / Natural / Unwashed is where the fruit is dried (often in the sun) on the bean and later removed (customarily by machine). This approach is often used in countries where rainfall is scarce and there are long periods of sunshine to properly dry the beans. The resulting beans are generally dustier.
The coffee is fruity, sweet, complex and heavier in body.
Semidry / Pulped Natural is where the skin of the fruit is removed immediately after picking, but the pulp is either allowed to dry on the bean with the pulp later stripped by machine or separated in fermentation tanks.
When done well, this produces the clarity of wet processing along with the fruity and floral notes associated with dry processing.
Honey processed coffees tend to be sweeter than the other types with more balance, less acidity and heavier body.
The cherry is pulped but none of the mucilage is removed. The coffee is then normally dried on raised (African) beds until reaching the optimum moisture content of 12%.
Within Honey processing are three main types that produce three different profiles: