||AB SL28, SL34, Batian
||Joseph Mugo Karaba
Kabumbu is a small coffee estate in Kirinyaga County, owned and managed by Joseph Mugo Karaba (pictured above). Joseph inherited the shamba (Swahili for ‘farm’) from his father, who first planted coffee in the 1960s. He and his family live on the estate which includes five acres of coffee trees and a small wet mill, where Joseph processes and prepares his coffees.
Kabumbu sits across 1,500-1,750 meters above sea level in the foothills of the extinct volcano, Mt Kenya. The area is defined by its bright red, nutrient-rich, volcanic soil and cool climate, both of which contribute to the outstanding quality of the coffees produced on this farm. Joseph grows SL-28 and SL-34 varieties on his farm, which were planted by his father when the shamba was established. The trees have been continuously regenerated since that time, using a stumping technique where new stalks are allowed to grow from the stump to replace older stalks, which are then cut back when the new stalks reach full maturation. In addition to these varieties, Joseph has chosen to plant a newer hybrid variety, Batian, which has been developed specifically for high yields and disease resistance, coupled with the potential for excellent cup quality.
Alongside the coffee shamba, Kabumbu Estate also has a small wet mill – or factory, as they are called in Kenya – on its land. This factory enables Joseph to process and dry his coffee crop onsite, rather than selling fresh, whole cherry to a local Farmers’ Society Cooperative. By processing his coffee independently, Joseph is able to control every step of the coffee’s production directly – from farming, to harvesting, processing, drying and sale – which helps him to ensure the full potential of his crop is achieved in terms of quality and price. The resulting coffee reflects the incredible amount of hard work and attention to managing every single variable that influences quality.
Choosing to process the coffee independently is not easy—or cheap. Managing processing on such a small scale has required significant investment in infrastructure, equipment and staff. It is also far costlier to process small volume lots than large day lots. This investment has paid off, however, as Kabumbu is now producing some exceptionally high-quality lots which fetch very high prices at the point of sale.
The coffee was carefully handpicked by Joseph and his team and sorted to ensure only the ripe cherries were processed. It was pulped using a disc pulping machine, which removes the skin and fruit from the inner parchment layer that protects the green coffee bean.
The coffee was then dry fermented for 16–24 hours, to break down the sugars and remove the mucilage (sticky fruit covering) from the outside of the beans. Whilst the coffee was fermenting it was checked and when ready it was rinsed and removed from the tanks.
The parchment-covered coffee was then washed in water channels with fresh water and sent to soaking tanks where it sat underwater for a further 24 hours. This process increases the proteins and amino acids, which in turn heightens the complexity of the acidity.
After soaking, the coffee was dried on raised drying tables (also known as African beds) and turned constantly to ensure they are dried evenly until they were at 11–12% humidity.
The coffee was then rested in parchment, and when ready for export, dry milled at Kahara Bowa mill in Thika, around a one hour drive from Nairobi.