Long Miles ‘Funny Bourbon’Natural Process Education Lot
- Roasts Wednesday, Ships Thursday
This lot was affectionately dubbed “Funny Bourbon” by the Long Miles team due to the fact that the plants are so visually different from the bourbons that are ubiquitous in Burundi. A naturally processed blend of SL28, harvested at Bukeye and Heza stations, this special release is an incredibly rare example of a non-bourbon variety separation from the country of Burundi.
Few coffee varieties have achieved the legendary status of SL28. Its name is instantly recognizable among coffee professionals, yet the story behind it is far less straightforward: a product of colonial-era breeding programs, a drought-resistant population from Tanganyika, and a genetic lineage that still raises questions today.
The “SL” designation traces back to Scott Agricultural Laboratories in Kenya, a coffee research center established in Kenya by the British colonial government in 1922 with the goal of developing high-yielding coffee varieties with improved resistance to drought and disease. In the early 1930s, a ‘Senior Coffee Officer’ with Scott Labs named A.D. Trench encountered a population of coffee growing in Tanganyika (present-day Tanzania) that appeared unusually tolerant of drought. He collected seed from this population and brought it back to Scott Labs, where subsequent trials confirmed its drought tolerance under Kenya’s local growing conditions. From there, this newfound plant material became known as Tanganyika Drought Resistant (TDR), and further research was pursued in earnest. Rather than releasing this heterogeneous population directly, Scott Labs selected a single outstanding tree from cultivated populations of TDR in 1935. This became the Selection 28, or SL28, that we still know and love today.
More recently, a genetic diversity study published in 2021 by Anthony et al. compared SSR markers from a large collection of cultivated Arabica accessions, including that of SL28. SSR (Simple Sequence Repeat) markers are small, repeated sections of DNA that vary between plants. Scientists can compare the number of repeats at specific locations in the genome between two plants to draw inferences about their genetic similarity. If two coffee varieties have the same SSR pattern across many markers, they are said to have the same DNA fingerprint, suggesting they are very closely related or potentially the same genotype.
During this study, researchers found that SL28 and an accession known as Coorg, originating from India, shared the same SSR fingerprint. Coorg is one of several historic Indian coffee selections, alongside Jackson, Kent, and Mysore, that are believed to descend from early Yemeni coffee introductions traditionally associated with Baba Budan’s 17th-century introduction of coffee to India. Given the matching SSR fingerprint between SL28 and Coorg, this raises the possibility that the TDR population from which SL28 was selected may have ancestry connected to Indian coffee introductions. However, no current genetic studies have confirmed this connection.
Nonetheless, while questions remain about the precise lineage of SL28, its status as Kenya’s most iconic coffee variety is beyond dispute. In recent years, renewed attention has been given to isolating Kenya’s traditional SL varieties amid the prevalence of disease-resistant cultivars such as batian and ruiru 11. This renewed appreciation has only reinforced what generations of coffee growers and drinkers have recognized: SL28 is not merely a historical artifact, but a truly exceptional variety whose distinctive cup profile continues to define Kenyan coffee.