Nav: Home > Coffee >

What are Kenya Coffee Varieties SL28 and SL34? Why Are Kenya AA Coffee Beans So Acidic

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, Professional coffee knowledge exchange For more coffee bean information Please follow Coffee Workshop (WeChat official account cafe_style) Located in East Africa Kenya is one of the main coffee-producing countries with about six million people nationwide engaged in the coffee industry mostly in the form of small farmers and cooperatives Kenya's coffee trees are mostly grown at altitudes of 1400-2000 meters with growing regions including Ruiri Thi

Professional Coffee Knowledge Exchange

For more coffee bean information, please follow Coffee Workshop (WeChat Official Account: cafe_style)

Kenyan coffee is exceptionally aromatic and brightly acidic. Just like the coffee beans chosen by FrontStreet Coffee from producing regions, they necessarily possess the unique and classic flavors of their origin. Maintaining flavor consistency is crucial. FrontStreet Coffee currently offers two Kenyan coffees: Assari AA and Sachini PB. Both are SL28/SL34 varieties. The selection reason lies in their different grades. PB, unlike AA, is a classification unrelated to grade and is commonly known as peaberries. The comparison between the two shows that PB is rounder and more solid, while AA is brighter and more lively.

Kenyan Coffee SL28 Variety

The Kenyan coffee SL28 variety is one of Africa's most famous and popular varieties. In recent years, it has gained renown for its remarkable blackcurrant notes and bright fruit acidity, becoming the most representative variety with the highest attention after Gesha. In fact, SL28 was first born in Kenya—just as Gesha originated in Ethiopia but achieved superstar status in Panama, SL28 has similar potential, shining from its cultivation grounds in Kenya to various coffee-producing nations.

Kenyan coffee SL28 is a direct descendant of Bourbon, selected and cultivated in the early 20th century by French and British missionaries and researchers in Kenya. It possesses mixed lineage from French Mission, Mocha, and Yemen Typica. High sweetness, exquisite balance, prominent citrus and plum flavors, intense and rich fruit acidity, full body, and beautiful balance—these are the distinctive flavor characteristics of Kenyan SL28.

About Scott Laboratories

Founded in 1922 by the colonial government, the Scott Agricultural Laboratory has now been renamed the National Agricultural Research Laboratories (NARL). The mission of Scott Laboratories was to "conduct extensive experiments on imported coffee varieties, research and select single tree plantings with ideal characteristics" and provide farmers with technical advice and cultivation training. Other work included yield experiments, grafting trials, pruning, shade cultivation experiments, and root cover crops. In 1944, the Kenyan government decided to transfer the coffee research station to the larger and better-equipped Coffee Research Foundation, which has been operating since 1949.

Origin of the SL28 Variety

According to literature, in 1931, a Scott Laboratories official conducted field surveys in Tanganyika (now Tanzania). He noticed a coffee tree variety in the Moduli district that seemed resistant to drought, diseases, and pests, so he collected seeds and brought them back to Scott Laboratories. In 1935, the laboratory selected single trees from the Tanganyika drought-resistant population and continuously improved them through breeding, eventually launching the Moduli descendant SL28. Recent genetic studies have confirmed that SL28 belongs to the Bourbon genetic group.

Characteristics of the SL28 Variety

The SL28 variety is easy to cultivate without special care. It produces large beans with high yields and excellent flavor quality. After being released by Kenyan authorities in the 1930s, it was first cultivated in Kenya, then spread to Uganda, and currently has gained widespread attention even in Central America. This variety is suitable for medium to high altitude areas and has drought resistance, but remains susceptible to major coffee diseases.

Coffee Flavor of the SL28 Variety

The flavor of the SL28 variety indeed carries the bright tones of original Bourbon and even the rich acidity of original Mocha, along with other complex flavors and rich texture. Although the yield of SL28 was later not as high as expected, the copper-colored leaves and broad bean-shaped beans offer wonderful sweetness, balance, and complex, varied flavors, as well as prominent citrus and plum characteristics, intense and rich fruit acidity, full body, and beautiful balance. Most notably, only when cultivated in Kenya can SL28 achieve such distinctive character; SL28 varieties grown in other countries only have similar flavors.

Kenya Isamama Processing Station - Qingcheng AB

Region: Central Region, Nyeri

Processing Station: Isamama Processing Station

Variety: SL28

Altitude: 1700-1890 meters

Processing Method: Washed

Kenya Isamama Processing Station - Qingcheng AB Roasting Profile

Preheat the drum to 150°C, add beans with heat at 120, damper at 3. Return temperature at 1'40", when drum temperature reaches 140°C, open damper to 4.

At 8'28", ugly wrinkles and black spots appear on the bean surface, with the toasted bread aroma clearly transitioning to coffee aroma, which can be defined as the prelude to first crack. At this point, listen carefully for the sound of first crack. First crack begins at 9'11", open damper to 5. Develop for 1'30" after first crack, discharge at 190.9°C.

Cupping

After our cupping, the specific flavor characteristics are as follows:

Chenyu AA has bright lemon acidity, grapefruit, and caramel aromatics. With temperature changes, it exhibits berry acidity and subtle floral notes. Overall, it has rich acidity with a juicy mouthfeel and a long, lingering aftertaste.