SL28 Coffee: The Kenyan Variety That Went Global
Key takeaways
SL28 was selected in 1935 at Scott Agricultural Laboratories in Kenya, from a single tree grown from drought-tolerant seed collected in Tanganyika (now Tanzania).
630 SL28 lots are in stock from 328 roasters; Kenya grows 440 of them, but Uganda (117), Costa Rica (36) and Colombia (34) follow.
Blackcurrant is the signature: it appears on 22% of Kenyan SL28 lots but only 5% of SL28 grown anywhere else.
Pure SL28 is rare in Kenya: only 23 of 440 Kenyan lots list it alone, while 50 of the 73 single-variety SL28 lots come from other countries.
Questions this article answers
What is SL28 coffee?
What does SL28 stand for?
What does SL28 coffee taste like?
What is the difference between SL28 and SL34?
Where is SL28 grown outside Kenya?
Is SL28 resistant to leaf rust?
SL28 is the reason a cup of Kenyan coffee can taste like blackcurrant cordial. It is also a 90-year-old lab selection with a catalogue number for a name, and it now grows on three continents.
There are 630 SL28 coffees in stock on Cuppd right now, from 328 roasters in 39 countries. Seven in ten are Kenyan, and our Kenya guide covers that side — the factories, the AA grades, the double washing. This page is about the variety itself: where it came from, what it tastes like when it leaves Kenya, and who sells the most of it.
Kenyan SL28 — blackcurrant, grapefruit, black tea
Where does SL28 come from?
From a drought-hardy coffee in Tanzania, picked out in a Kenyan lab. In 1931 A.D. Trench, the senior coffee officer at Scott Agricultural Laboratories in Kenya, toured what was then Tanganyika and found a drought-tolerant coffee in the Moduli district. Seed went back to Scott Labs, and in 1935 the station selected a single tree from it. That tree was number 28.
Selection: picking one outstanding plant out of a population and growing its seed on, rather than cross-breeding two parents. SL28 was a selection — nobody crossed anything to make it.
Scott Agricultural Laboratories was set up by Kenya's British colonial government in 1922, and its coffee section ran a selection programme through the late 1930s that gave every promising tree an 'SL' number. SL28 was the star. World Coffee Research places it in the Bourbon side of the Arabica family, describes it as a tall tree with large beans, low yields and exceptional cup quality at altitude, and notes that some Kenyan SL28 trees are still productive at 60 to 80 years old.
Its weakness is disease. SL28 is susceptible to leaf rust, coffee berry disease and nematodes, which is why Kenya later bred resistant varieties on top of it: Ruiru 11 in 1985 and Batian in 2010. Both list SL28 in their parentage, so even the 'replacements' carry a bit of it.
Fun fact
SL34, SL28's usual bag-mate, has a messier backstory. It was selected from a tree on the Loresho Estate in Kabete that was supposedly descended from French missionaries' Bourbon seed — but genetic tests now link SL34 to the Typica group instead.
What does SL28 coffee taste like?
Dark fruit and sharp acidity, with blackcurrant on top. Across all 630 lots, blackcurrant is the most common note at 17%, then caramel (11%), and chocolate, blackberry and grapefruit (10% each). Roasters used 184 different notes for it, but that blackcurrant-grapefruit pairing is what separates SL28 from almost everything else on the shelf.
Processing decides how much of it you get. Washed SL28, 482 lots and three-quarters of the shelf, is the classic: blackcurrant on 21% of washed lots, blackberry and grapefruit on 12% each. Natural SL28 (136 lots) is a different coffee — strawberry on 20%, chocolate and cherry on 15% each — and blackcurrant drops to 5%. If you want the blackcurrant, buy washed.
And the famous savoury note is real but small. Tomato appears on 13 SL28 lots — 2% — and every one of them is Kenyan. Hibiscus is more common, on 33 lots (5%).
Does SL28 taste the same outside Kenya?
No — and this is the most useful thing to know about the variety. Blackcurrant appears on 22% of Kenyan SL28 lots but on only 10 of the 190 lots grown anywhere else: 5%. Take the same plant out of Kenya's soil, altitude and very strict washing, and the signature note mostly goes with it.
What replaces it depends on where it lands. Ugandan SL28 (117 lots, much of it from the Rwenzori Mountains and Mount Elgon) is the comfortable one: chocolate on 19%, caramel on 15%, cherry on 12%. Costa Rican SL28 (36 lots) is the floral, fruity one — hibiscus on 28% of lots, strawberry on 19% and honey on 17%. For the country itself, see the Costa Rica guide.
Uganda and Costa Rica — chocolate, strawberry, hibiscus
Uganda deserves a closer look, because it is SL28's real second home. The variety appears on 117 of the 267 Ugandan coffees in stock — 44%, against 67% in Kenya — usually alongside SL14 (95 of those 117 lots) and often Nyasaland (39). It shows up there with fewer of the sharp edges: blackcurrant appears on just 4 Ugandan lots and grapefruit on 2, against chocolate on 24. If Kenyan coffee has ever tasted too intense for you, a washed Ugandan SL28 is the gentler way into the same variety.
Some growers outside Kenya do chase the original. A handful of the Colombian, Panamanian and Honduran SL28 lots in stock still list blackcurrant — they are the small minority, which is exactly why they are interesting to taste.
SL28 in Latin America — Colombia, Panama, Honduras, El Salvador, Costa Rica
Why is pure SL28 so rare in Kenya?
Because Kenyan farms grow it mixed, and the bag tells you so. Of the 440 Kenyan SL28 lots in stock, only 23 list SL28 alone. 344 also list SL34 — 78% — and 314 list Ruiru 11 or Batian as well. Smallholders deliver cherry from mixed plots to a shared washing station, so a Kenyan lot is usually a field blend of all four.
Field blend: a single lot made from several varieties growing side by side on the same farms and picked together. It is still single-origin coffee — the mixing happens on the tree, not in the roastery.
The irony is that if you want to taste SL28 on its own, you are more likely to find it outside Kenya. Of the 73 single-variety SL28 lots in stock, 50 come from other countries: Costa Rica 17, Colombia 12, Uganda 8, El Salvador 4, Honduras and Myanmar 3 each. Kenya still dominates the variety — SL28 appears on 440 of the 653 Kenyan coffees in stock, about two in three — but the pure version is mostly a Latin American thing now.
Which roasters sell the most SL28?
Most roasters carry one, and a few carry a whole Kenyan menu. Of the 328 roasters selling SL28, 186 have exactly one lot in stock, and 18 carry five or more. The top two hold 31 lots between them, 5% of the shelf.
Five Senses in Australia leads with 18, split between Kenya (12) and Uganda (6). Goriffee Roastery in Slovakia has 13, every one with Kenyan coffee in it and 12 of them washed — a factory-by-factory menu. Sample Coffee, also Australian, has 10, all washed: nine Kenyan lots and a pure SL28 from Colombia.
Behind them come Cafés San Agustín and Olisipo at nine each, then Red Rooster, Bella Barista and Supremo at eight. Bella Barista is the odd one out: every one of its eight has Ugandan coffee in it.
How should you buy your first SL28?
Buy a washed Kenyan first. That is where the blackcurrant lives, and it is the reference point everything else gets measured against. Brew it as filter and drink it black: the acidity that makes Kenyan SL28 famous is exactly what milk flattens.
Then buy a pure SL28 from somewhere else — a Costa Rican honey or a Colombian washed lot — and taste them side by side. Same variety, different place, and the difference is not subtle. That comparison teaches you more about what a variety does to flavour than any chart, though our coffee varieties explainer is a decent place to start.
SL28 is a 1930s drought selection that ended up defining what a Kenyan coffee tastes like, and then left home. Browse all 630 SL28 coffees in stock, start with a washed Kenyan, and rate it on Cuppd so the next person knows which lot actually tasted of blackcurrant.
How did we count 630 SL28 coffees?
Every number on this page is a count from the Cuppd catalogue, not an estimate or a survey. Specifically:
- Source: the product listings on 940 specialty roasters' own online shops, not marketplaces or resellers. A coffee counts once per roaster listing.
- In stock: every coffee is re-checked against the roaster's shop once a month. All 630 SL28 lots here were confirmed available on 2 October 2026.
- Variety: as the roaster labels it. 'SL-28' and 'SL28' are merged; SL34, SL14, Ruiru 11 and Batian are counted as their own varieties and are not in these figures.
- What counts as an SL28: any coffee whose roaster lists SL28 among its varieties, including Kenyan field blends. 73 of the 630 are pure SL28; 557 list other varieties too, 48 combine several origins and 27 are named as blends.
- Tasting notes: the roaster's own notes, mapped onto a shared vocabulary of 330 notes so that spelling variants and near-synonyms count as one note. A lot can list several notes, so shares do not add up to 100%.
- Not ranked: nothing here is scored or sponsored. The roasters above are ordered by how many SL28 lots they stock, nothing else.
SL28 on the price index
October 2026€66 per kg at the median, +14% vs all coffees. Half of SL28 coffees cost between €56 and €77/kg, across 641 coffees from 356 roasters.
See the Cuppd Specialty Coffee Price Index →