Ideally in this process the coffee berries should be uniformly ripened, but often in practice they are harvested by stripping all the berries at once from the trees and collecting them on the ground beneath.
The berries are gathered from the ground and spread out in the sun where they are raked so that they are evenly exposed.
Initially the microorganisms and the enzymes inherent in the coffee berry after the pulp and mucilage. Then the red skin, pulp, mucilage and parchment fuse to produce a thick hull as they dry out.
The coffee is called “pergamino” at this stage. This hull is removed in a hulling machine that simultaneously polishes off most of the silverskin layer.
Before the tough silverskin can be removed, the beans must be soaked in water. The moistened silverskin can then be removed mechanically and the beans are dried again before storage and shipping.
The dry method produces green coffee beans much less expensively than the wet method. A high proportion of Brazilian Arabica coffee is processed in this way and almost all Robusta coffees are treated in this way.
The final beverage produced from dry processed coffee has a full flavor that is often described as hard and sometimes is characteristic of a region, for example Rio coffees.
The dry method is generally the less controlled of the two main methods. The stages where extra care could be introduced after harvesting are where the coffee berries may be washed and sorted by flotation before being dried and during then drying itself.
The risk of fungal damage to the berries and consequently to the beans is vey high if the berries are too heaped.
They need to be spread out very thinly, to be frequently raked and not resoaked by rainfall.
Green Coffee Processing: Dry Method
