Kenyan coffee is renowned for its exceptional quality, several varieties having gained worldwide recognition. Notably, K7, Ruiru 11, and the SL series, particularly SL28 and SL34, have garnered significant attention. These varieties owe their name to the Scott Agricultural Laboratories (now the National Agricultural Laboratories, NARL), established by the British colonial government in Kenya in 1922. Research conducted at these labs led to the development of SL28 and SL34 coffee strains, which have since become popular worldwide.
Among these varieties, Kenyan SL28 is particularly distinguished as one of Africa's most revered coffee varieties. Originating from a single 'Tanganyika Drought Resistant' coffee tree specimen in what is now Tanzania in 1935, SL28 is celebrated for its resilience to drought, disease, and pests. Over time, it has spread to other African regions such as Uganda, Malawi, and Zimbabwe, and more recently to Latin America.
Its sister variety, Kenyan SL34, was selected from a single tree on the Loresho Estate in Kabete, Kenya, in the late 1930s. Despite advances in disease-resistant varieties and hybrids, the SL series remains a favorite among Kenyan coffee producers as they offer longevity, high yields, and exceptional coffee quality.