In dry processing (sometimes called the “dry method,” “natural method” or “unwashed method”), the mucilage, along with the exocarp and endocarp, is left intact during drying. Heavier debris can be removed from ripe cherries by a hydraulic separation process - much like The Wet Process - or by winnowing. Whether or not this is done, the cherries are spread in sunlight on patios or raised to dry and ferment, just like grapes are dried into raisins.
Ripe cherry selection and even drying is important, so as best as possible to prevent uneven fermentation between the cherries. As the cherries dry, the exocarp, mesocarp and mucilage attach to the endocarp from the outside-in and the mucilage will ferment around the parchment and the seed underneath these other layers. After drying down to 11-12% moisture and temporarily stored, the dried cherries are sent to the mill, where all exterior layers are then removed via hulling and preparation for shipment begins.
Dry processing is the oldest and simplest coffee processing method because it requires no additional equipment or access to water; only space for drying. Drying this coffee takes longer, however - a recommended 22-24 days versus 12-14 for the wet-processed.. Taking twice as long to dry, they therefore require double the drying space as wet processed coffees.
Dry-processed coffees tend to possess more body, as well as fruity-ferment notes. They can come from all over the world, but the best-known are from Ethiopia, where elevations can climb more than 1,930 meters. Dry-processed coffees from Ethiopia can be tart, with blueberry and even raspberry notes.