From Cafe Imports:

Chelbessa

This coffee comes from the Chelbessa Washing Station in Yirgacheffe. Chelbessa is one of the largest “Kebeles” or towns in Gedeb. This washing station receives coffee from nearly 500 farmers in the region. 

Coffees in Ethiopia are typically grown on very small plots of land by farmers who also grow other crops. The majority of smallholders will deliver their coffee in cherry to a nearby washing station or central processing unit, where their coffee will be sorted, weighed, and paid for or given a receipt. Coffee is then processed, usually washed or natural, by the washing station and dried on raised beds.

The washing stations serve as many as several hundred to sometimes a thousand or more producers, who deliver cherry throughout the harvest season: The blending of these cherries into day lots makes it virtually impossible under normal circumstances to know precisely whose coffee winds up in which bags on what day, making traceability to the producer difficult. We do, however, make every available effort to source coffee from the same washing stations every year, through our export partners and their connections with mills and washing stations.

Typically farmers in this region don't have access to and therefore do not utilize fertilizers or pesticides in the production of coffee. 

Natural Process (aka Sun-Dried or Dry Processed)

Fruit Removal: After drying
Fermentation: Occurs inside the fruit mucilage surrounding the seed and under the pulp, will take place as long as there is fuel available to the microorganisms (e.g. sugar, moisture, acids, etc); the seeds typically become inhospitable to microorganisms when they reach 11% moisture
Drying Time: Up to 30 days on average, weather permitting.
Profile: Noticeably fruity or “pulpy” flavors, often described as “boozy” or “winey”; can also have strong nutty and/or chocolate characteristics, and typically has a heavier or syrupy body.

While Washed coffees have their fruit removed relatively quickly after harvesting, Natural or “Dry” process coffees are something like the opposite, in a manner of speaking: The fruit is instead picked when ripe and allowed to dry completely around the seed before being husked or hulled off. While historically this hulling was done by hand with a kind of mortar-and-pestle setup, today it’s done by machinery that can be finely calibrated. Natural process coffees are most commonly found in Ethiopia, Yemen, Brazil, and Costa Rica, though producers around the world are also experimenting with this methodology.

As with all coffee preparation, there is fermentation occurring during the processing, from the moment the coffee is picked (or possibly earlier, whenever an access point is created in the fruit). Local or intentional populations of yeast and bacteria will enter the fruit at the access point and begin to metabolize the sugars and acids inside the coffee fruit immediately, a process that can continue until the coffee is dried to the standard of 11% moisture. While the coffee itself is not held in “fermentation tanks,” its fermentation process can be altered by things like ambient temperature and exposure to full sun or shade; depth on the drying bed; rotation of the coffee during drying, etc.

(Note: At Cafe Imports, we typically avoid describing these coffees as “Sun-Dried” and instead prefer the term “Natural,” since many other coffees are also dried under the sun. We also avoid using the term “Unwashed,” which is common in some parts of the world.)

Drying Natural coffees is considerably longer and the overall process is riskier than for Washed coffee, which hints at some reasons the Washed technique was developed: Naturals take more space on drying surfaces, require more attention and labor (to prevent mold and infestation during drying, for example), and are constantly at potential risk for spoilage or “overfermentation,” as the fruit material that is intact on the seeds provides a longterm and concentrated fuel source for yeast and bacteria to metabolize.

Natural processing is the oldest basic technique for preparing coffee, and in ancient times (as well as currently in some cultures and applications), it’s possible that the coffee fruit was allowed to dry completely while still on the branch, allowing it to be harvested only when needed. Modern Natural coffees are harvested ripe and intentionally dried, typically on patios, raised beds, or drying tables; they cannot be dried in mechanical dryers as Washed coffees can.