Why does the SL28 coffee seeds varieties stand out?

SL28 is a Kenyan selection made in the 1930s at the former Scott Agricultural Laboratories, now the National Agricultural Laboratories in Kabete. It suits medium to high altitudes, tolerates drought but is prone to disease, and its cup is elegant with floral notes. Front Street's Cherry Tomato beans combine SL28 and SL34.

The variety spread from Kenya into other Arabica-growing areas such as Uganda and later reached Latin America. Old SL28 trees in Kenya, aged 60 to 80 years, still bear fruit today, which says something about its resilience. Front Street Kenya Cherry Tomato comes from the Asali honey processing station at 1550-1750m, with a 72-hour washed process and notes of snow pear, smoked plum, yellow sugar, cherry tomato, and plum.

SL28 is one of Africa's most legendary coffee varieties. Since being selected in Kenya in the 1930s, it gradually spread to other Arabica-growing regions such as Uganda, and in recent years it has traveled even farther to Latin America. It is suited to cultivation at medium to high altitudes, is drought-tolerant yet susceptible to disease, and its flavor is extremely elegant, often with floral notes. Front Street's Cherry Tomato coffee beans are precisely a combination of SL28 and SL34, displaying layers of snow pear, smoked plum, and yellow sugar. This article will trace the breeding history of SL28 at the Scott Agricultural Laboratories, sort out its genetic relationship with the Bourbon genome, and introduce specific information about Kenya's Asali processing station, helping coffee enthusiasts fully understand this variety's origins and potential in the cup.

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SL28 occupies an extremely prominent and highly respected position among African coffee varieties. Precisely for this reason, after it was first selected in Kenya in the 1930s, it gradually spread to other parts of Africa, playing an important role especially in Uganda's Arabica-growing belt, and today it has even crossed the oceans to take root in Latin America. This variety is suited to growing at medium to high altitudes, has relatively strong drought resistance, yet is prone to coffee diseases. Nevertheless, its flavor performance is quite outstanding, often carrying elegant floral notes. Front Street's Cherry Tomato coffee beans are made from a combination of SL28 and SL34. SL28 is known for its toughness—its quality means that even after long periods without care, or even after being abandoned for years or decades, it can still recover and produce well again. In many parts of Kenya there are old SL28 trees aged 60 to 80 years that continue to bear fruit to this day.

Front Street Kenya Cherry Tomato Coffee Beans

Country: Kenya Region: Asali (Honey Processing Station) Altitude: 1550-1750m Varieties: SL28, SL34 Processing Method: 72-hour washed processing Flavor: Snow pear, smoked plum, yellow sugar, cherry tomato, plum

Front Street Coffee has learned that the breeding of SL28 began at the former Scott Agricultural Laboratories (now the National Agricultural Laboratories, or NARL, located in Kabete). Between 1935 and 1939, the laboratory carried out single-tree selection work, and all selected lines were named with the SL prefix. Researchers selected from 42 coffee trees of different origins and systematically evaluated their yield, quality, and tolerance to drought and disease. SL28 was selected in 1935 on the basis of a single tree from a drought-resistant plant population named Tanganyika.

In 1931, AD Trench, then Senior Coffee Officer at the Scott Laboratories, traveled to Tanganyika (present-day Tanzania) for an inspection. According to historical records, he discovered in the Moduli area a coffee variety that appeared able to resist drought, pests, and diseases. He collected seeds and brought them back to the Scott Laboratories, subsequently confirming its drought-resistant characteristics. This variety was once widely distributed until it was replaced by its descendant SL28. Recent genetic testing has confirmed that SL28 is genetically related to the Bourbon genome.

The History of the Scott Agricultural Laboratories

The Scott Agricultural Laboratories (now called the National Agricultural Laboratories, abbreviated NARL) were established in Kenya in 1922 by the British colonial government. The laboratory conducted agricultural research on behalf of the Ministry of Agriculture and also provided technical advice and training to Kenyan farmers. The laboratory employed entomologists, mycologists, and plant breeding experts. The coffee department was originally located in the department's central office, moved into the laboratory in 1934, and 24 acres of land were set aside specifically for coffee research. The unit's name comes from the historical background of its buildings.

These buildings were constructed in 1913 and were originally used as a sanatorium. During World War I they were requisitioned as a field hospital. The buildings were named after Dr. Henry Scott, a missionary from the Scottish Church. After the Ministry of Agriculture took over these buildings in 1922, it called them the Scott Agricultural Laboratories. Kenya's Scott Agricultural Laboratories, together with the Lyamungo Research Station in Tanganyika, became major coffee breeding centers in East Africa.

Research work was carried out in the laboratory and also in cooperation with private estate owners. Historical records from the laboratory state: "The trial planting of introduced varieties was a notable feature of the laboratory's work... while selections were also made from individual trees showing desired characteristics." Other coffee research work included comparative yield trials, grafting trials, evaluation of pruning effects, shade trials, and cover crop studies. In 1944, Kenya decided to transfer coffee research to a dedicated coffee research station in order to provide better facilities for field experiments. Jacaranda Estates (located 20 miles north of Ruiru), covering 380 acres, officially began operation in 1949. In addition, substations were successively established in Upper Kiambu in 1957, Meru in 1958, Kitale in 1938, Lake Victoria in 1959, and Kisii in 1957.

The above content is compiled by CoffeeHunters, a coffee news website.