In this process, water is the emphasis. The coffee cherry is brought to the wet mill where it is then pulped (outermost fruit skin is removed).
Next it is put in water with any floaters being discarded as defects.
Then, the coffee is fermented (fruit mucilage layer broken down), washed to remove the remaining fruit, and then dried on a patio, raised screen bed, or by using a mechanical dryer.
The parchment stays with the green bean until it is milled at the dry mill. With this process, the coffee tends to have flavor characteristics that are brighter, a cleaner cup, and a lighter body.
Some of the countries known for their washed coffees are Indonesia, Ethiopil and Yemen, Guatemala...