semi-washing treatment

The difference between the semi-washing method and other processing methods is that the coffee beans are not directly sun-dried to a moisture content of 11-12% in the process, but the hard surface is removed when the moisture content is about 30-35%. The shell exposes the surface of the green beans directly, and then continues to dry in the sun until it reaches a moisture content that is not perishable and convenient for storage. This secondary drying method makes the coffee beans present a swamp-like dark green appearance.
Semi-washed coffee beans have lower acidity and a thicker character. The flavor of semi-washed coffee is between natural and washed. This processing method is popular in Indonesia. Mandheling mostly adopts the semi-washed method. Brazil has also begun to use the semi-washed method in recent years.
The semi-washing method is somewhat similar to the water-washing method. First, the skin and part of the pulp of the coffee cherry berries are removed, and then the berries are dried in the sun. After the berries are dried, they are moistened, and then the pulp is removed with a special machine to remove the seeds.

Source: https://www.lebrewlife.co/blogs/coffee/56100