SL14
SL14 is the Scott Laboratories selection nobody puts on a bag. Its two stablemates, SL28 and SL34, are the reason buyers fly to Kenya. SL14 was picked out of the same programme, at the same station, in the same decade — and it ended up somewhere else entirely: it is a workhorse plant, valued for surviving dry seasons and cold nights rather than for what it does in the cup, and today it matters more in Uganda than in Kenya.1
The name works the same way as the others. SL is the filing prefix for Scott Agricultural Laboratories, the Kenyan research station that made the selections; 14 is the serial number of that particular tree.
It is worth saying plainly what the trade-off is. World Coffee Research rates SL14’s cup at high altitude “Good.” It rates SL28 and SL34 “Exceptional.” SL14’s compensation is that it asks for less: less water, less warmth, less fertiliser.123
Where it came from
Everything in this section comes from the World Coffee Research variety record for SL14, read directly. WCR’s catalogue, maintained by World Coffee Research, is the specialty industry’s reference database for coffee varieties.1
- SL14 was selected in 1936, at Scott Agricultural Laboratories in Kenya.
- It came from one single tree, labelled “Drought Resistant II” — usually written D.R. II. The name is the whole brief: this was material chosen because it kept producing through dry weather.
- Seedlings of D.R. II were established at Kabete in 1933 — Kabete being the site of Scott Labs, just outside Nairobi — and then distributed widely across the areas east of the Rift Valley in Kenya.
- Nobody knows where D.R. II itself came from. WCR records that the historical documentation of its origin was lost. So the parent population is a dead end: the paper trail stops at a label on a tree.
- Genetic testing puts SL14 in the Bourbon-Typica group, Typica related — the same side of the Arabica family tree as Typica and as SL34, and the opposite side from SL28, which tests as Bourbon-related.13
- It is economically important in both Kenya and Uganda.
That last point is the interesting one. SL28 travelled as a flavour; SL14 travelled as a survivor. The two Kenyan varieties everyone can name are grown for the cup, and the Kenyan variety almost nobody can name is grown because it lives.
The lost-parent problem is not a footnote. Its sibling SL34 came from a tree labelled “French Mission” and turned out not to be a Bourbon at all, which is how this wiki knows the Scott Labs paperwork can be wrong. With D.R. II there is no paperwork left to be wrong about — the Typica-group placement comes from the DNA and from nothing else.
To verify
WCR’s own page is internally inconsistent on the date. One sentence says SL14 was “originally selected in Kenya the late 1930s”; another says it was “selected in 1936 from a single tree.” 1936 is mid-decade, not late. Proud Mary Coffee repeats only the vaguer “late 1930s.”4 The specific year fits the documented 1935–1939 window of the SL selection programme recorded in the SL28 and SL34 notes, and 1936 is the more precise claim, so this note uses it — but no primary Scott Laboratories document was located to settle it, and the existing SL28 note already flags an unresolved dispute over Scott Labs’ founding date and successor institution. The same uncertainty applies here.
To verify
One source gives a different reason for the selection entirely. KOTA Coffee — now trading as Artefact — writes that SL14 was “originally developed in the 1930s to improve resilience against disease.”5 That is flatly at odds with WCR, which names the parent tree “Drought Resistant II” and rates SL14 susceptible to every major disease in the catalogue. Drought and disease are not the same problem and SL14 only solves one of them. Treat the disease-resistance framing as an error in a roaster-facing page, not a competing account.
What the plant is like
From the World Coffee Research record, read directly:1
| Trait | SL14 |
|---|---|
| Stature | Tall |
| Leaf tip colour | Light bronze |
| Bean size | Average |
| Yield potential | Medium |
| Quality potential at high altitude | Good |
| Nutrition requirement | Low |
| Ripening | Not recorded |
| Cherry-to-green-bean outturn | Average |
| Drought | Tolerant |
| Cold | Tolerant |
| Coffee leaf rust | Low resistance / susceptible |
| Coffee berry disease | Susceptible |
| Nematodes (root-attacking soil worms) | Susceptible |
Read down that column and SL14 is a study in “average, but cheap to keep.” Nothing is exceptional except the two tolerances — and the disease line is a disaster, exactly as it is for SL28 and SL34. The whole Scott Laboratories programme selected for yield, hardiness and cup, and none of the three surviving selections got any defence against fungus. Proud Mary Coffee says the same thing in one line: SL14 is “vulnerable to all major coffee diseases.”4
Cold tolerance is SL14’s genuinely distinctive trait, and it is rare enough to be worth pausing on. Neither SL28 nor SL34 is rated for it. Arabica is a subtropical highland plant that stops growing and eventually dies back when nights get too cold, so a variety that shrugs at cold nights can be planted higher up the mountain, or further from the equator, than one that does not. Paired with the drought tolerance, that is what makes SL14 a smallholder’s plant: it forgives bad weather in both directions.
Nutrition requirement is Low — the plant produces a medium crop without much fertiliser. For a farm buying inputs on credit, that is often the number that decides what gets planted, and it is where SL14 beats SL34 outright (rated Medium).3
Optimal altitude is given as a sliding scale, because latitude and elevation trade off against each other — the further from the equator, the lower a farm can sit and still get cool enough nights. WCR’s thresholds are the same for all three SL varieties: above 1,200 m between 5°N and 5°S, above 900 m at 5–15°, above 700 m beyond 15°.
WCR also records a planting density of 1,000–2,000 plants per hectare under single-stem pruning — that is, a farm growing each tree as one main trunk rather than a multi-stemmed bush. It is a wide spread, and it is the sort of figure that gets adjusted per farm rather than followed.
SL14 next to SL28 and SL34
The three Scott Laboratories selections in WCR’s catalogue, side by side:123
| SL14 | SL28 | SL34 | |
|---|---|---|---|
| Selected | 1936 | Early-to-mid 1930s | Late 1930s |
| From a tree labelled | ”Drought Resistant II” | Tanganyika Drought Resistant population | ”French Mission” |
| Genetic group (WCR testing) | Typica-related | Bourbon-related | Typica-related |
| Leaf tip colour | Light bronze | Green | Dark bronze |
| Bean size | Average | Large | Large |
| Yield potential | Medium | Low | Medium to low |
| Quality at high altitude | Good | Exceptional | Exceptional |
| Nutrition requirement | Low | Low | Medium |
| Drought | Tolerant | Tolerant | Not rated tolerant |
| Cold | Tolerant | Not rated | Not rated |
| Disease | Susceptible to all three | Susceptible to all three | Susceptible to all three |
| Where it matters today | Kenya and Uganda | Kenya, Uganda, Malawi, Zimbabwe, Latin America | Almost entirely Kenya |
The single row that explains SL14’s whole commercial life is the quality row. “Good” is a perfectly respectable rating — it is the same band WCR gives Ruiru 11, the disease-resistant variety Kenya spent decades breeding — but it is not what the specialty trade pays a premium for, and it sits beside two stablemates rated a band higher. Genuine Origin, a green-coffee supplier, puts it bluntly: SL14 “was similarly selected from a tree in Kenya for its drought resistance but yields a lower cup quality than SL28.”6 That is a relative judgement, not a score, but it agrees with WCR’s rating and this note treats the ranking as settled.
The reverse comparison is the fair one. SL14 needs less fertiliser than SL34, out-yields both of the others, and is the only one of the three rated for cold. If you are choosing a tree to survive on a marginal smallholding rather than to win a cupping table, SL14 is the better plant.
Where it is grown
Kenya is where it was selected and where it was first distributed, east of the Rift Valley. But SL14’s centre of gravity has shifted: it is now strongly associated with Ugandan Arabica, particularly the high slopes of Mount Elgon — the extinct volcano straddling the Kenya–Uganda border — and the Rwenzori Mountains on Uganda’s western edge.15
Working altitudes quoted by people actually buying and selling Ugandan SL14 cluster in a narrow band:
| Source | Stated altitude | Region | |
|---|---|---|---|
| 1 | KOTA / Artefact Coffee5 | 1,400–2,000 m | Uganda, around Mount Elgon |
| 2 | Mountain Harvest (Ugandan exporter)7 | 1,300–2,000 m | Mount Elgon and Rwenzori |
| 3 | Sandbox Coffee / Agri Evolve8 | 1,500–2,000 m | Rwenzori |
Only the first of those was read directly. Taken together they describe the same working range — roughly 1,300–2,000 m — which sits comfortably above WCR’s 1,200 m equatorial threshold. These are operational figures from companies describing their own supply chains, not survey data.
What it tastes like
World Coffee Research’s formal rating at high altitude is “Good.” Everything more specific comes from roasters and exporters selling the coffee, so read it as marketing-adjacent description rather than measurement.
KOTA / Artefact — the one such page confirmed by reading it — describes Ugandan SL14 as berry-like sweetness, citrus notes and subtle floral hints over a rounded body, and gives lime, blackberry and yoghurt as the notes on one specific Ugandan lot.5 The recurring shape across the sources consulted is a clean, balanced, mild-to-bright cup with soft red fruit and a little floral lift — pleasant and unremarkable, which is exactly what a “Good” rating predicts.
Ugandan SL14 is conventionally washed. See Washed process, and Cupping and Coffee scoring for how cup quality is actually assessed.
To verify
Producer sources contradict each other on disease resistance, and the disagreement is not small. Proud Mary Coffee says SL14 is “vulnerable to all major coffee diseases.”4 Mountain Harvest, a Ugandan exporter, describes it as “moderately disease-tolerant.”7 WCR’s trait table backs Proud Mary — susceptible to rust, coffee berry disease and nematodes, with no resistance recorded anywhere — and this note follows WCR. The Mountain Harvest description was not read directly (the research behind this note cites a social-media post, which could not be retrieved), so it is recorded as a claim, not weighed as evidence. A grower should not plant SL14 expecting it to hold off disease.
To verify
Two lot-level descriptions could not be confirmed. The German roaster Sandbox Coffee is reported to sell a washed SL14 and SL28 lot from the Rwenzori region, sourced through the Ugandan exporter Agri Evolve from roughly 200 smallholder farmers at 1,500–2,000 m, with notes of blackcurrant and delicate florals.8 Its product page returned HTTP 429 on two attempts and was never read. The Mountain Harvest figures in the table above come from a Facebook post that likewise could not be retrieved.7 Both are plausible and neither is verified — treat the farmer counts, altitudes and flavour notes as claims attributed to those companies.
To verify
No numeric cupping scores, auction prices, buyers’ contracts or competition placements could be verified for SL14 — at all. No Cup of Excellence, Alliance for Coffee Excellence, Best of Panama or Specialty Coffee Association record isolating SL14 as the variety in a placed or auctioned lot was located. There are structural reasons to expect exactly this: neither Kenya nor Uganda runs a Cup of Excellence programme, Kenyan lots are sold at the Nairobi Coffee Exchange by screen-size grade such as “Kenya AA” rather than by variety, Ugandan Arabica is largely aggregated across smallholders, and SL14 is frequently milled together with SL28 anyway. The paperwork that would carry a variety-level score mostly does not exist. Any specific SL14 price or score figure is a synthesis, not a citation.
To verify
Nothing was found about who, if anyone, controls the variety. No plant breeders’ rights, patent, trademark or licensing arrangement for SL14 appears in any source consulted, and WCR’s record does not discuss legal status. On the evidence, SL14 behaves as an openly propagated public selection out of a colonial-era government research station — which is what you would expect — but that is an absence of documents, not a document saying so. The same gap exists in this wiki’s SL28 and SL34 notes. Kenya’s coffee breeding programme now sits with KALRO; whether it maintains SL14 mother stock is unknown.
Related
- SL28 — the famous stablemate, drought-tolerant like SL14 but rated a full band higher in the cup
- SL34 — the third Scott Labs selection, also Typica-related, also disease-defenceless
- Scott Agricultural Laboratories — the Kenyan station that selected all three
- Typica — the genetic group WCR’s testing places SL14 in
- Bourbon · Bourbon-Typica group — the family framework the classification sits inside
- Kenya — where it was selected and first distributed
- Uganda — where it matters most today
- Mount Elgon · Rwenzori Mountains — the two Ugandan highland regions it is grown in
- World Coffee Research — keeper of the variety catalogue this note leans on
- Coffee leaf rust · Coffee berry disease — the diseases it has no defence against
- Ruiru 11 · Batian — the disease-resistant Kenyan varieties bred later, and the ones that share SL14’s “Good”-to-”Very good” cup band
- KALRO — the Kenyan state body that now holds the country’s coffee breeding programme
- Nairobi Coffee Exchange — why Kenyan lots are recorded by grade rather than by variety
- Washed process — how Ugandan SL14 is conventionally processed
- Cupping · Coffee scoring — how a “Good” rating would be measured
- Climate change and coffee — the reason a drought- and cold-tolerant variety is worth more attention than its cup score suggests