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Kenyan Coffee Development, Coffee Growing Regions, Coffee Grading, and Introduction to SL28/SL34 Coffee Varieties

Published: 2026-01-28 Author: FrontStreet Coffee

Last Updated: 2026/01/28, Kenya is located in eastern Africa, crossed by the equator, with the East African Rift Valley running north-south. It borders Somalia, Tanzania, Ethiopia, and South Sudan, with the Indian Ocean to the southeast. The coastal areas are plains, while most of the country consists of highlands with an average elevation of 1,500 meters. Many volcanoes stand tall, particularly in the central highlands

Geography of Kenya

Kenya is located in eastern Africa, crossed by the equator and traversed from north to south by the East African Rift Valley. It borders Somalia, Tanzania, Ethiopia, and South Sudan, with the Indian Ocean to the southeast. The coastal region consists of plains, while the majority of the country comprises highlands with an average elevation of 1,500 meters. Numerous volcanoes also stand tall, including the dormant volcano Mount Kenya in the central highlands, reaching an impressive altitude of 5,199 meters.

Kenya landscape showing highlands and mountains

History of Kenyan Coffee Development

Although Kenya borders Ethiopia, the birthplace of coffee, its coffee industry developed relatively late. The first coffee trees were introduced to Kenya in 1893 by French missionaries from Réunion Island. Later, under British colonial rule, coffee was cultivated in large estates, with all produced coffee beans being exported to London. It wasn't until the Coffee Ordinance was passed in 1933, establishing the Kenya Coffee Board, that coffee sales operations were moved back to Kenya. An auction system was established in 1934 and continues to be used today. In 1935, the government drafted a coffee quality grading system proposal. By the 1950s, the government passed an agricultural bill known as the "Swynnerton Plan," which granted farmers land ownership, enabling them to achieve self-sufficiency and increase their income.

Kenyan Coffee Grading System

Therefore, Kenya uses the same grading system for both domestic consumption and export sales. The grading is based on coffee bean size and quality as indicators, with clear specifications for coffee bean size. The grades are divided into AA+, AA, AB, PB, C, E, TT, and T. Among these, the most commonly available grades in the market are AA, AB, and PB.

Kenyan Coffee Growing Regions

Kenya has numerous coffee-growing regions: Bungoma, Embu, Kiambu, Kirinyaga, Kisii, Machakos, Meru, Mt. Elgon, Murang'a, Nakuru, Nyeri, Thika, Taita Taveta, and Trans-Nzoia. There are 14 growing regions in total, with Nyeri, Kirinyaga, Murang'a, Kiribwe, and Thika being the most renowned.

The SL28/SL34 Coffee Varieties

When it comes to Kenya's most important and distinctive coffee varieties, SL28/SL34 stand out. SL28/SL34 were initially selected in the 1930s and were primarily cultivated in Kenya and other African regions, later spreading to Latin America for cultivation. These varieties are suitable for medium to high altitude areas and have good drought resistance, though they are susceptible to coffee diseases. Between 1935-1939, Scott Laboratories selected 42 different coffee trees and assigned the SL prefix to study their yield, quality, drought resistance, and disease resistance. SL28 was selected in 1935 from a single tree in the Tanganyika drought-resistant population, and genetic testing has shown that SL28 is related to Bourbon genetics. SL34 was selected from a tree at the Loresho Estate in Kabet, Kenya, with genetic testing indicating its relation to Typica genetics.

Scott Laboratories and Legacy

Scott Laboratories was established in Kenya in 1992 by the British colonial government to conduct agricultural research for the Ministry of Agriculture and provide technical support and training to Kenyan farmers. However, it has now been transformed into the Kenya National Agricultural Laboratory (NARL). Currently, SL28 trees are planted in many parts of Kenya, with a history of 60-80 years, yet they remain productive.

FrontStreet Coffee's Kenyan Offering

Among these offerings, FrontStreet Coffee has acquired Kenya Asali AA TOP coffee beans from Thika. This particular FrontStreet Coffee Kenya AA TOP is made from the SL28 variety and processed using the refined Kenyan 72-hour washed method (K72). When brewed using 15g of FrontStreet Coffee Kenya beans with a 1:15 coffee-to-water ratio at approximately 92°C water temperature for pour-over preparation, the finished cup reveals flavors of cherry tomatoes and black plums upon first sip. The acidity is bright, the mouthfeel is clean, and the afternote carries the sweetness of brown sugar with the characteristics of green tea.