All coffee cherries are hand-sorted before a pre-pulp float, where underripe or damaged cherries and foreign objects are removed. The cherries are then floated in pre-pulping tanks to remove any floaters before being pulped. The coffee is fermented in dedicated concrete tanks for 12 hours, during which the fermented parchment is agitated several times throughout the day through ceremonial foot-stomping.

After fermentation, the coffee moves into a large serpentine grading channel, where it's separated into different density grades. During washing, the parchment is continuously agitated to encourage lower-density parchment to float and to remove any remaining mucilage. After grading, the parchment receives a final rinse. The coffee then moves to a pre-drying area where workers hand-sort the parchment to remove any insect-damaged, discoloured, or chipped beans. Finally, the parchment is laid out to dry and turned regularly throughout the day for 30 days.

In Rwanda, Raw Material works alongside Muraho Trading Co. This partnership helps affiliated cooperatives improve their production quality, secure higher coffee prices, and access new markets. Understanding the specific challenges faced by Rwandan coffee producers will be an ongoing process in the coming years.

Through this collaboration, they are developing an incentive-based model that encourages producer participation while maximizing impact. Raw Material sources coffee from Muraho's washing stations across Rwanda's Nyamasheke, Gakenke, and Nyabihu regions.

Gisheke station, situated in Nyamasheke District, overlooks Lake Kivu. Nearly half of its coffee cherries arrive by boat from Mushungwe Island. In fact, all cherries from neighbouring islands must be delivered by boat, as Gisheke is only accessible by water.

Gisheke's location is perfectly suited for processing and drying natural coffees, thanks to the steady wind currents flowing between two steep hills that lead toward Lake Kivu, Idjwi Island, and the Democratic Republic of the Congo.

Bourbon is one of the most culturally and genetically significant varieties of Arabica coffee in the world. This tall variety is characterized by relatively low production and susceptibility to major diseases. However, it produces excellent cup quality when grown at high altitudes.

The first Bourbon plantation dates back to 1715 when the variety was introduced from Yemen to Bourbon Island, now known as La Réunion. Bourbon traces its origins to a broad group of C. arabica specimens that developed naturally and is still cultivated in Central America today.

Depending on the sub-group, Bourbon coffee can produce red, yellow, or orange-coloured cherries. The plant's shoots initially grow upwards at a 45° angle to the stem, and the stems are sturdy. Young leaves are green, and the plants generally have broader leaves and rounder fruit and seeds than Typica and its descendants.

The washed process was designed to minimize the risk of off-flavours caused by uncontrolled fermentation during the natural process. Cherries are typically sorted using a flotation tank, where under-ripe or defective fruits float to the top and can be removed. The remaining cherries are then pulped and left in a tank to ferment until the sticky fruit mucilage is soft enough to be washed off the parchment—a paper-like layer surrounding the seed.

The design and cleanliness of the tanks are crucial, and the degree and speed of fermentation depend on various factors. These include the amount of fruit remaining, the presence of bacteria and yeasts, whether the tank is filled with water, and the environmental conditions.

Once the mucilage has sufficiently degraded, it's washed away with water. The remaining parchment coffee, as it's commonly called, is then dried until it reaches a safe moisture content. The bacteria-rich and sugary water used in the process must be treated carefully, as it can cause algae blooms if it enters streams and rivers.

In situations where large amounts of coffee are processed in bulk, such as in Ethiopia, some operations have found it economical to use a mechanical demucilager. This device removes all the fruit from the parchment with minimal water, bypassing the fermentation stage entirely. However, some believe this leads to a reduction in cup quality, as many flavour precursors are created through fermentation.