Situated just west of the sparkling blue (and perilous) waters of Lake Kivu, the Kanzu station is nestled amidst lush green hills that cultivate coffee, sugar cane, and bananas. The fertile expanse surrounding the ancient volcanoes, where ash accumulation enriches the soil with minerals, serves as the ideal terrain for cultivation. Smallholder producers tend to modest plots of bourbon variety coffee, interwoven with sustenance crops like bananas and beans.
The cherry collection at Kanzu station kicks off in March, extending its harvest activities until July. Employing meticulous management and harvest planning, the station meticulously segregates the harvest into distinct outturns, a practice reminiscent of the process in Kenya. Upon arrival at the washing station, cherries undergo a preliminary quality check through flotation to separate the less dense ones.
Subsequently, a Mckinnnon disc pulper delicately removes the outer skin of the cherry, revealing a mucilage-covered seed. This seed undergoes a dry fermentation process lasting up to 18 hours. To manage runoff and erosion effectively, the wastewater from the processing is treated with Effective Microorganisms (EMTechnologiesTM), safeguarding precious water resources for the local community.
The community surrounding Kanzu station has been the focus of targeted aid efforts since the mid-'90s, marking a transformative period for the Rwandese coffee industry in the aftermath of the genocide. A significant contributor to this progress has been the initiatives led by USAID and Dr. Tim Schilling, who spearheaded the establishment of collection stations and the development of cooperatives. Their dedicated work has paved the way for the remarkable market access that Rwandan specialty coffee has enjoyed over the past decade.
WASHED PROCESSED COFFEES
The washed process begins with coffee cherries delivered to the washing station, both from the primary market or from farmers bringing their coffee directly to the mill. The cherries are inspected, and an initial quick round of hand-sorting separates the defective coffees before placing them into the hopper. They are then funneled to the depulper, which removes the fruit from the seeds (beans). After that phase is done, the coffee is fermented underwater for approximately 12-36 hours. During this fermentation, a microbial de-mucilagation takes place, which allows the outer fruit and pectin layer to break down, making the coffee easier to dry. This phase also crucially alters the organic acids within the coffee, as sugars and organic acids are transformed, with the best washed coffees maintaining their complex fruit esters. Once the fermentation is complete, the parchment is emptied into the washing channels, where it is agitated with rakes to remove the last of the fruit layer. During this step, the water is refreshed to ensure its capability of separating the fruit layer from the seed. Once the washing is complete, the coffee is taken to the raised drying tables for sun drying.