Natural process, dry process, unwashed, or natural sundried all refer to the same method of processing that usually involves drying coffee cherries either patios or raised beds in the sun. To prevent the cherries from spoiling, they are raked and turned throughout the day and then covered at night or during rain storms. This process, which can take 3-6 weeks normally, is the more-traditional method of processing coffee. This process of drying the cherries out in the sun originated in places without reliable access to water and usually works best in areas with low humidity and infrequent rain — such as parts of Ethiopia and Yemen — although we do have some farmers using the natural process in other places.
After the cherries have been dried to the optimum level, they are sent to mills to separate the seeds from the rest of the dried fruit, otherwise known as being “hulled.”
Because the seeds of natural sundried processed coffee are encased in the cherry for longer, the resulting flavors from this process are generally more fruity and fuller-bodied. The natural sugars in and around the seed are infused into it during this process and result in a higher sugar content than washed coffees.
The Washed Process
The second process is the washed or wet process. In this method, the cherries are removed from the seeds before the drying process. To do this, the cherries are first sorted to ensure consistent ripeness levels, and then are run through depulpers—machines that squeeze the cherries until the seeds pop out. Then the seeds and skins are separated, and the seeds move into tanks where they go through either a ferment-and-wash method or a machine-assisted wet process to remove the rest of the mucilage—the remaining fruit—to clean the seeds before they are dried.
In a ferment-and-wash process, the remaining mucilage is broken down by microbes and yeast via fermentation and then is washed with water again to remove the mucilage from the seeds. In a machine-assisted process, the cherries are mechanically scrubbed and most of the mucilage of the seen is removed through friction. After the seeds are washed, they are dried in the sun on patios, raised beds, or in machines.
Washed coffees, on the other hand, result in flavors more inherent to the bean itself, rather than the pulp and skin.