Selected in 1935 by the Scott Agricultural Laboratories, SL28 is one of the most celebrated varieties in the coffee world. This is its verified history — and that of the Huila lot already being sold in the United States.
Few coffee varieties inspire as much devotion among cuppers as SL28. It was born in a Kenyan agricultural lab in the 1930s, became the heart of the classic Kenyan profile — that juicy blackcurrant acidity — and today, nearly a century later, it's also grown in the mountains of Colombia. This guide gathers what's verified about the variety, what's still debated, and the story of a Colombian SL28 lot already being sold in the United States.
SL28 is a variety of Coffea arabica selected in 1935 by Kenya's Scott Agricultural Laboratories. It belongs to the Bourbon genetic group, is drought-tolerant, tall-growing and low-yielding, and is famous for an exceptional cup at high altitude, with notes of blackcurrant and citrus fruit.
The prefix 'SL' comes from Scott Laboratories: each selection from the lab received a serial number, and 28 turned out to be the one that went down in history. According to World Coffee Research, it's one of the best-known and most respected varieties in Africa, and its cup quality at high altitude is rated as exceptional. It's not a 'modern' lab variety in today's sense: it's a single-tree selection made with the methods of ninety years ago, and that's exactly why its story is worth telling well.
The mother seed was collected in 1931 by A. D. Trench in Tanganyika (today Tanzania), from a population they called 'Tanganyika Drought Resistant'. In 1935, the Scott Agricultural Laboratories selected a single tree from that population in Kenya, and all the SL28 that exists today descends from it.
For decades its exact parentage was debated. What the recent genetic testing cited by World Coffee Research confirmed is that SL28 does belong to the Bourbon group. The Scott Laboratories — today Kenya's National Agricultural Laboratories — distributed it across the country, and from there it passed to Uganda, Malawi and Zimbabwe. A fact that says a lot about its hardiness: in Kenya there are SL28 trees 60 to 80 years old that are still producing, and coffee fields abandoned for years that resumed producing once taken up again.
SL28's classic profile is intense, juicy acidity, a silky body and a distinctive blackcurrant note, alongside citrus, red fruit and sometimes hints of sweet tomato in washed Kenyan lots. It's a complex, vibrant cup that's relatively easy to recognize blind.
A fair caveat, though: that profile describes above all the washed Kenyan SL28, which is the historical benchmark. When the variety is planted in another terroir and processed differently — for example, an experimental natural in Huila — the cup changes: the fruit becomes riper and more wine-like, and the fermentation adds layers of its own. The variety sets the potential; the soil, the altitude and the process decide how much of that potential is expressed and in which direction.
Because it pays for its cup with demanding agronomy: low yield, susceptibility to leaf rust, coffee berry disease (CBD) and nematodes, according to World Coffee Research. In return it offers drought tolerance, a large bean and a high cherry-to-parchment conversion. It's a bet on quality, not volume.
That explains why you don't see SL28 on just any farm. A grower who plants it is accepting fewer kilos per hectare and more care for the lot, in the hope that the price for quality makes up for it. In countries with high leaf-rust pressure — like Colombia — that decision is even braver: there's no genetic resistance to protect it, only management. That's why SL28 lots outside Africa tend to be small, experimental and from producers who know exactly what they're doing.
Yes, though in very small volumes. The variety reached Latin America in recent years through specialty producers seeking to stand out, and Huila is one of the focal points. A concrete, verifiable example: Edinson Argote's SL28, in Oporapa, Huila, which Dif≠erente roasts in Manizales.
This is the kind of detail only we can give because we know the lot: Edinson Argote grows SL28 on the Quebraditas farm, in the mountains of Oporapa. Dif≠erente — the roasting house of Carlos Escobar, 2024 National Filter Coffee Champion and third in the world at the 2025 World Brewers Cup in Jakarta, Colombia's first-ever world final — selected that lot for its catalog. And there's an external sign it's no local whim: the U.S. retailer Slow Pour Supply sells this very SL28 from Differente in the United States. A coffee that leaves Oporapa, is roasted in Manizales and sells out at a U.S. specialty shop is no longer a promise: it's a lot that travels.
Edinson Argote's lot is an experimental natural: the cherry is dried whole, with double fermentation and specific yeasts to achieve reproducible profiles. It's a process that amplifies the variety's fruit and adds wine-like and sweet notes a classic washed wouldn't give.
Here it's worth being direct: a natural SL28 from Huila won't taste like a washed SL28 from Nyeri, and it doesn't try to. What's interesting about this lot is precisely the crossover: legendary Kenyan genetics, a Huila terroir and a controlled-fermentation process designed by the producer. If you want to understand what the variety contributes and what the process contributes, tasting this coffee alongside a washed Kenyan is one of the most educational cupping exercises you can do. The SL28 Natural by Edinson Argote is available in our store for $85.000.
In Colombia, SL28 lots are scarce and tend to sell as microlots that run out. Ours — SL28 Natural · Edinson Argote · $85.000 — is roasted in Manizales for filter methods. We recommend V60 or pour-over methods with ratios around 1:16 so the acidity and fruit express cleanly.
Being a fermented natural, it needs no extreme temperatures or exotic recipes: water between 92 and 94 °C, a medium grind and attention to contact time are enough for an expressive cup. If you're coming from commercial coffee, brace yourself: SL28's acidity is not a defect, it's the trait that made this variety a legend. And if you want to keep exploring coffee genetics, in our varieties hub you'll find the rest of the guides in the series.
Try the SL28 Natural by Edinson Argote — $85.000 See all the variety guides
Published by Dif≠erente · Manizales · 2026-10-14