FLOW STATE Espresso

Bishan Guracha Station sits at 2,050 meters above sea level in Worka (Nensebo), in the West Arsi Zone of Ethiopia’s Oromia region. The name “Bishan Guracha” comes from a large local river and means “black water” in the local language. The station sources coffee from the nearby Roricho and Bohira kebeles, working closely with around 250 dedicated supplier farmers and processes both washed and natural lots.

Rather than using mechanical demucilation, which is becoming very popular in Ethiopia due to its efficiency, this coffee is processed using more traditional methods. Upon arrival at the station, red cherries are pulped the same day to remove the outer skin and then fermented for 72 hours to break down and remove mucilage. The parchment is then thoroughly washed after fermentation to ensure all of the mucilage is removed before being spread on raised beds to dry under the sun for 12-15 days depending on weather conditions.

In botanical terms, heirloom varieties are plants passed down through generations, often within families, known for their historical significance and cultural heritage. In Ethiopia, "heirloom" is often used as a catch-all term for any variety native to the country. Estimates suggest there are between 10,000 and 15,000 heirloom varieties in Ethiopia today, most of which have not been formally genetically identified.

While many heirloom varieties originate as wild plants, some have been selected for their desirable qualities and cultivated on coffee farms across the country.

Heirloom varieties typically fall into two categories: JARC varieties and regional landraces. JARC varieties are developed and researched by the Jimma Agricultural Research Centre for desirable characteristics, such as greater disease resistance or increased yield. In contrast, regional landraces are varieties that have evolved naturally over generations, adapting to their specific environments.

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.