Understanding Kenyan Coffee Varities
When it comes to Kenyan coffee varieties, most cafés or roasteries always have the variety SL28 or SL34 at the top of their list. It's true that the SLs are well known coffee varities to give a good cup full of flavor but there’s more to Kenyan coffee varities than what you can only get from the SL coffee varieties. Here’s an in-depth but to the point overview of the most common coffee varieties available.
French Mission Bourbon
The French Mission Bourbon is a very important Arabica variety in a cultural sense. The name Bourbon originated from the island (now known as Reunion Island) that French missionaries took the variety from. The Reunion island is an overseas region of the French republic and is an island in the Indian Ocean with a volcanic rainforest interior. Later in the 1800s the French missionaries brought the Bourbon variety to Africa and more so to Kenya. The year is estimated to be 1897 and the name remained that way because of the introduction of the variety by the French Missionaries.
The French Mission Bourbon as a tree is quite tall with average yield and a potentially good cup at high altitudes. Typically, the medium sized coffee beans exhibit Arabica flavors being dark and bold coffee varieties. However, the coffee is highly susceptible to leaf rust and coffee berry disease. Today it is not quite easy to find it in Kenya and is only still found in a handful of estates that are still operational from the colonial period.
SL14, SL34 and SL28
The SL varieties were discovered in the early 1900s by Scott’s Laboratories hence the abbreviation; SL. The Sl varieties are considered to be revolution to the Kenyan coffee industry. In the quest for a more tolerant variety, it is said that Scott’s Laboratories discovered a variety that was draught resistant in Tanzania which was later brought into Kenya for testing. This later introduced its progeny, SL28.
SL28 is a tall coffee tree with high yields and an exceptionally good cup profile. It is drought but is still susceptible to leaf rust and coffee berry disease but not the extent of the French Mission Bourbon. SL28 is related to the Bourbon genetic group.
SL14 was developed around the same period of time in the 1930s. Historical records surrounding SL14 are not available but the seedlings were developed in Kabete and distributed though out Kenya. The SL14 has a good cup profile but not as good as the SL28.
SL34 is a similarly tall tree an exceptional cup profile as the SL28 but is highly susceptible to coffee berry disease.
SL28 still remains the variety that really stood out held ground amongst the Scott’s Laboratory varieties in Kenya. One of the reasons is that SL28 is predominantly the most successful of these varieties is because the variety can be left for long periods of time, even decades unattended to and still be easily revived and start producing. This means that there is still generational flow of coffee production over the years.
The visual differences between SL28 and SL34 is manly the leaf tips. SL34 tends to have dark bronze leaf tips while SL28 could have green or bronze (almost yellow) leaf tips.
The Kenyan coffee market was highly saturated with the SLs and was doing quite well until a coffee berry disease broke out that saw a dip of an almost half of Kenya’s production in 1967. This necessitated the coffee research foundation in Ruiru, Kenya to develop a variety that can endure such tough times. They developed an F1 hybrid which was coined; Ruiru 11 from the location of the research facility.
An F1 hybrid is an apparent crossbreed between two completely different parents to give a new generation with a uniform combination of characteristics from each parent. It is hence safe to say that the Ruiru 11 variety got its characteristics from different existing varieties. They selected varieties such as SL28 abd SL34 for their good cup taste and varieties such as the Sudan Rume for coffee berry disease resistance and added the Catimor variety that added an extra cushion for resistance to coffee berry disease and tolerance to leaf rust.
Ruiru 11 is known to be a dwarf tree with a good cup profile and high yielding capability due to the hybrid vigor from the “crossbreed”. Kenya’s coffee market to date now has a substantial volume of Ruiru 11 which farmers now prefer due to its low cost of handling because its resistance to coffee berry disease. Ruiru 11 has now become part and parcel of Kenyan coffee with farmers going to the extent of grafting the root system of the SL 28 and SL 34 with Ruiru. They do this to gain both ways from the cup quality of SL 28 and 34 with the resistance and productivity of Ruiru 11.
A way to visually identify Ruiru 11 is its leaf tips which are dark green. The nodes are quite close to each other if compared to SL 28 which has wider spaced nodes.
Named after the highest peak of Kenya’s highest mountain; Mount Kenya, Batian was developed to still exhibit resistance to coffee berry disease and tolerance to leaf rust and have the similar taste profile to SL 28 and 34. The main difference between Ruiru 11 and Batian is simply that Batian was developed to typically have a better taste profile and still enjoy the same or slightly less resistance to disease as compare to Ruiru 11.
Batian is a tall variety with a very good cup profile and good yield at high altitudes and good farming practices. Batian has a quick maturation period and can have its first year of production in two years.
However, out of experience, Batian varieties are biennial; whereby they produce well once every two years. Batian variety still hasn’t grasped root in Kenya but I believe that it is part of the future for Kenyan varieties. Batian’s appearance is quite similar to the SL 28 with green or bronze leaf tips, however SL 28’s primaries are much longer and droop further.
K7 and Blue Mountain
K7 was developed around the same time period with the SLs and was indeed developed by Scott's Laboratories. It has quite a high tolerance to coffee leaf rust coffee berry disease. Its quite commonly planted in low altitude areas around Kenya. K7 is also said to be Bourbon related.
Little is known about the Blue Mountain variety in Kenya and is not widely grown. Little is also known of its origin and how it got to Kenya, but for the volumes available from the Kenyan blue mountain, its reputably noted for its full body structure, flavor and gentle aroma. Blue mountain is mostly found around the Mount Elgon area of Western Kenya and around the Aberdare Range in central Kenya