SL28

History

In the 1930s the colonial government of Kenya commissioned Scott Agricultural Laboratories — the "SL" in the name — to select coffee trees suited to Kenyan conditions, combining yield and quality. In 1931, researchers selected SL28 from a drought-resistant tree originating in Tanzania (then Tanganyika). Its yield was not the highest, but its cup quality was outstanding, and it soon became one of Kenya's leading varieties. SL34, selected in the same period from a French mission estate in Kenya, is better suited to wetter high-altitude areas. Today the two are often grown together, and Kenyan lots are frequently labeled "SL28, SL34."

Flavor Profile

SL28 is a favorite among coffee connoisseurs:

• Blackcurrant: its signature acidity
• Complex fruit: plum, berries, grapefruit, even tomato
• Bright and juicy: vivid acidity often described as juice-like
• Body: a full texture with a winey finish

SL28's distinctive flavor comes not just from the variety but also from Kenya's high-altitude volcanic soils, its two harvest seasons and the country's characteristic double-fermentation washed processing.

Growing Information

• Key trait: excellent drought tolerance with a deep root system, suited to Kenya's highlands
• Altitude: best above 1,500 m
• Disease resistance: low; susceptible to leaf rust, coffee berry disease and nematodes
• Stature: tall, with bronze-tipped new leaves and large beans

SL28 Beyond Kenya

Its outstanding flavor has led to plantings in Uganda, Tanzania, Costa Rica and elsewhere. SL28 grown in Central America often keeps its vivid berry acidity, though usually in a softer style than in Kenya.

Successor Varieties

To combat coffee berry disease and leaf rust, Kenya later released resistant varieties such as Ruiru 11 and Batian. Batian in particular comes closer to SL28's cup quality and is gaining recognition in the specialty market.

Brewing Tips

SL28 suits light to medium-light roasts brewed as pour-over to show off its juicy acidity and blackcurrant. Try 92–94°C water and a 1:15–1:16 ratio; if the acidity feels too sharp, grind a little finer or extend the brew to bring sweetness forward.