In traditional Ethiopian specialty natural processing, cherries are spread in a thin layer over a raised bed and dried in indirect or direct sunlight.
For supernatural processing, cherries - hand harvested and selected via Brix measurement at their optimum ripeness - are weighed and spread evenly in a thick layer on raised drying racks lined with plastic sheet. The sheet is then rolled up (a bit like a burrito) and the cherries are fermented for a pre-determined amount of time. Unlike a strict anaerobic fermentation there is some limited oxygenation. After the fermentation period the coffee is shade dried in a thick layer. The precise recipe is a closely guarded secret and varies for each washing station with adjustments to fermentation time, cherry volume, and thickness of drying layers making up the possible variables.
In order to ensure consistency, prevent over-fermentation, and avoid mould formation, it is essential that the conditions are strictly monitored throughout. Temperature, Brix and moisture readings are recorded periodically and small adjustments to airflow and ambient temperature are made accordingly.
Once the optimum moisture content has been reached (around 12.5%) the cherries are rested in a cool environment prior to secondary processing (hulling, grading, sorting, handpicking and bagging in Grainpro for export).