VUNGA, Fully Washed

Upon delivery at the washing station, all cherry is hand-sorted before a pre-pulp float, removing underripe or damaged cherry, along with any foreign objects.

After sorting, the fruits are pulped and the seeds are fermented in dedicated concrete fermentation tanks for around 12 hours. During this time, the sticky, fermenting parchment coffee is agitated several times throughout the day. This encourages lower density seeds to float to the top and helps to clean any residual mucilage off the parchment.

After fermentation, the coffee is released into a large serpentine grading channel. This process helps to wash away the fruit residue and also separates the parchment into different density grades. After a final post-wash rinse, the coffee is taken to a pre-drying area where it’s hand-sorted removing any insect-damaged, discoloured or chipped seeds. The coffee is laid out to dry and turned on a regular basis for a period of 30 days. This slow drying is really beneficial for quality and longevity.

Vunga is a well-established small cooperative run by President Uwimana Daphrose. She partnered with Muraho Trading Co. to access export and financing support, helping Vunga improve quality, earn higher prices, and reach new markets.

Though located in an area where little coffee is produced, Vunga has earned a reputation for extremely high-quality coffee. The washing station placed 13th in the 2012 Rwanda Cup of Excellence and 4th in 2014.

A premium of $0.35 USD per kilo of milled green coffee goes to the Vunga cooperative to fund infrastructure upgrades. This premium supported the installation of a full serpentine washing system (previously lacking), extended drying tables, and a de-pulper in 2017. Through the cooperative, Vunga's producers receive bonus second payments and health insurance.

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 used for fermentation are crucial, and the type, degree and speed of microbial activity depends 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.