SL28 — Kenya's Blackcurrant Signature
Historical milestone, not our tasting review
These profiles describe events, farms, varieties and notable coffees. Numbers reported by competition organizers or other reviewers are not our tasting scores; we do not convert those numbers into five-star ratings. Where a precise historical result cannot be matched to a specific lot, year and primary record, we leave it unscored.
What the evidence cannot establish: SL28 is a variety, not a single lot. World Coffee Research documents the 1935 selection and agronomic traits, but it does not assign one numerical taste score, competition result or auction price to all SL28 coffees.
Our evidence and rating standards →What was it?
SL28 is a Bourbon-related Arabica variety selected from one tree in Kenya in 1935 at Scott Agricultural Laboratories. World Coffee Research identifies its source population as 'Tanganyika Drought Resistant.' It is not one single coffee lot and does not have a universal tasting score.
Who grew it?
Scott Agricultural Laboratories selected SL28 in Kenya; growers later cultivated it across East Africa and beyond. The variety was not developed by one identifiable contemporary coffee farm or farmer.
Where?
First selected in Kenya from plant material associated with Tanganyika (present-day Tanzania). SL28 is now grown in Kenya, Uganda and other origins, with flavor and performance varying by location and management.
What made it important
Developed by Scott Agricultural Laboratories between 1935 and 1939, SL28 was selected for its drought resistance and exceptional cup quality, quickly becoming a flagship variety for Kenyan coffee production. Its historical significance is rooted in its unique genetic profile, which is linked to the Bourbon group and responsible for the signature blackcurrant and wine-like acidity that defines the Kenyan coffee profile globally. The variety is noted for its rusticity, with many trees planted in the mid-twentieth century remaining productive today after decades of growth. Despite its high susceptibility to major coffee diseases, it remains a cornerstone of the industry due to its resilience and ability to produce high-quality yields with minimal fertilizer inputs.
How was it processed?
SL28 is a genetic variety, not a processing method. Coffees made from SL28 can be washed, natural or otherwise processed; the processing used must be verified for each specific lot.
What did reviewers say?
Many published Kenyan coffee descriptions mention blackcurrant and bright acidity, but these are sensory descriptors, not guaranteed traits of every SL28 lot. This historical variety profile is not an original tasting review.
What did it change?
Its history illustrates how plant genetics, agronomic resilience and cup quality can pull in different directions. A specific lot's flavor still depends on cultivation, ripeness, processing, roasting and brewing.
Where is that producer today?
World Coffee Research documents SL28 in Kenya and other African countries and reports continued cultivation beyond Africa. Its susceptibility to disease helps explain growers' interest in alternatives; this does not establish that classic SL28 has disappeared.
Sources & further reading
External articles and records support specific historical details; a source does not independently verify every statement on this page. Unlinked research notes are identified separately, not presented as citations.