Rume Sudan

Rume Sudan is a plant the coffee world uses as a spare-parts bin. It barely yields, it is hardly ever planted commercially, and most drinkers will never see it on a bag — yet its genes sit inside Ruiru 11, Batian and CATIE’s Centroamericano, three of the varieties that let farms keep growing coffee where disease had made it impossible.¹

It was collected as wild coffee, not bred from a farm population, which is exactly why breeders wanted it: wild material carries defences that centuries of cultivated Bourbon and Typica had lost. Roasters usually write the name the other way round, as Sudan Rume; the two are the same plant, and this wiki uses Rume Sudan because that is the form the breeding literature and the World Coffee Research catalogue use.¹

In the last decade a handful of Colombian producers have started growing it on purpose, as a single variety, and selling tiny washed lots at collector prices. That is the reason a variety with almost no commercial acreage has a public reputation at all.

The origin dispute

This is the one thing about Rume Sudan that sources genuinely do not agree on, and it matters, because it is the difference between a South Sudanese wild coffee and an Ethiopian one.

To verify

Ethiopian landrace, or wild coffee from the Boma highlands of South Sudan?

World Coffee Research — the specialty industry’s reference catalogue, and the most authoritative source available here — describes Centroamericano as a cross between T5296 and “the Ethiopian landrace variety Rume Sudan.” Read directly, the page names Ethiopia and does not mention Sudan at all.¹ This wiki’s CATIE note already carries that wording.

Every roaster-facing source consulted says something different: that the variety was collected as wild coffee in the Boma Plateau / Boma highlands, in what is now South Sudan, immediately across the border from Ethiopia. JBC Coffee Roasters puts it as “what is now South Sudan’s Boma Plateau just across the border from Ethiopia” — confirmed by reading the page.² The research report behind this note attributes the same Boma account to two further sellers, La Cabra and Xliii Coffee; neither page could be retrieved to check (the servers returned HTTP 429), so they are recorded here as unverified restatements and are deliberately not listed as sources below.

The likeliest reconciliation — and it is inference, not documentation — is that both are pointing at the same borderland: the Boma highlands sit on the Sudanese side of a wild-Arabica region whose centre of origin is Ethiopian, and “Ethiopian landrace” may be a loose shorthand for that genetic origin rather than a collection location. No source states that reconciliation, and no primary collection record was located. The name itself, which carries “Sudan” in it, favours the Boma account; WCR’s authority favours the other. Do not state either as settled fact.

What is not in dispute is the character of the material: it is wild-origin, collected rather than bred, and it entered breeding programmes as a source of resistance genes rather than as a crop.¹²

To verify

The collection year and the RS-510 designation rest on single, unretrievable sources. The research report behind this note gives 1940 as the year researchers first collected the variety, attributed to Xliii Coffee, and an official designation of RS-510 attributed to La Cabra. Both pages were unreachable when checked (HTTP 429), and neither claim appears in any source that was successfully read. Treat “the 1940s” and “RS-510” as trade lore until a breeding-programme document confirms them. RS-510 is listed as an alias on this note only so that readers searching the code land here.

What the plant is like

Rume Sudan’s agronomy is easy to summarise and hard to source precisely, because there is no World Coffee Research record for it — the catalogue documents its descendants, not the parent.

The one trait every source agrees on is very low yield. That single fact explains the variety’s entire history: a plant that produces too little cherry to pay a farm’s bills will not be planted commercially, so it survives in germplasm collections and breeding blocks instead of fields. JBC Coffee Roasters states it plainly — “exceptionally rare,” “very low yielding,” and therefore “rarely grown as a single origin coffee and most often used as a stock of high quality genes for new hybrid varietals.”²

The second trait is disease resistance, and it is the reason breeders kept it. This wiki’s Coffee berry disease note records Rume Sudan and the Timor Hybrid as the two sources of resistance cited over and over in the CBD literature, with major resistance genes sitting at three separate loci in Arabica. Rume Sudan is the Arabica answer to coffee berry disease — the Timor Hybrid gets its resistance from Robusta — which is why Kenyan breeders reached for it when they needed resistance without the cup penalty that Robusta genes bring.

To verify

Plant measurements, rust resistance and growing countries come from one unretrievable roaster page. The research report attributes to Xliii Coffee the following: trees of 2–2.5 m with flexible, sturdy branches; stronger resistance to coffee berry disease and Coffee leaf rust than Bourbon and Typica; cultivation today in Colombia, Ethiopia and Kenya; and a typical altitude band of 1,700–1,800 m. That page returned HTTP 429 and could not be checked, and no second source corroborates any of the four. Note that the altitude band in particular is contradicted by the actual Colombian lots documented below, which run from 1,570 m to 1,900 m — so treat 1,700–1,800 m as a rough middle, not a limit.

Separately, the same report claims Rume Sudan is an ancestor of SL28. This wiki’s SL28 note, sourced to the World Coffee Research SL28 record, says SL28 was selected from a single tree in the Tanganyika Drought Resistant population and tests as Bourbon-related — nothing about Rume Sudan. The two plants are related in the other direction: Rume Sudan and SL28 are both parents of Ruiru 11 and Batian, which is an easy claim to invert. Do not state that Rume Sudan is an ancestor of SL28.

What it was actually for: breeding stock

This is the part of the story that is well documented, because the offspring all have catalogue records. Rume Sudan appears in the pedigree of three widely planted modern varieties, each recorded on this wiki against the World Coffee Research catalogue:

Variety	Released	Bred by	Where Rume Sudan sits
Ruiru 11	1985, Kenya	Coffee Research Foundation (now KALRO)	In the complex male parent, alongside K7, SL28 and N39 — the quality-and-resistance side of the cross
Batian	2010, Kenya	Coffee Research Foundation (now KALRO)	One of seven contributors, with SL28, SL34, N39, K7, SL4 and the Timor Hybrid
Centroamericano	2010, Central America	CIRAD–CATIE–ICAFE–IHCAFE–PROCAFE–ANACAFÉ	The direct second parent: T5296 × Rume Sudan1

Two of those three are Kenyan, and the reason is Coffee berry disease. Kenya’s 1968 CBD epidemic destroyed roughly half of national production, and the breeding programme that followed needed resistance genes that would not wreck the cup. Rume Sudan was one of the few Arabica sources on offer.

Centroamericano is the clearest demonstration of what the variety is worth. It is an F1 hybrid — the first generation of a cross between two genetically distant parents, unusually vigorous but unable to breed true from saved seed — combining T5296’s rust resistance with Rume Sudan’s wild genetics. World Coffee Research credits it with production increases of 22–47% over the standard varieties in Central America and “exceptional cup quality potential when well-managed at high altitudes.”¹ A wild plant that cannot pay its own way produced a commercial variety that beats the standards on both yield and flavour.

The Colombian single-variety lots

Since roughly the 2010s, Colombian producers have planted Rume Sudan as a crop rather than as breeding stock. Two farms account for nearly everything on the market.

	Las Margaritas	Granja Paraiso 92
Producer	Café Granja La Esperanza	Wilton Benítez
Region	Caicedonia, Valle del Cauca, Colombia	Piendamó, Cauca, Colombia
Altitude	1,570–1,850 m3	1,900 m4
Processing	[[Washed process	Washed]]3
Tasting notes as sold	Eucalyptus, jasmine, lemon peel3	Red candies, cherry cola, juicy red grape acidity, long sweet tropical finish4

Both rows were confirmed by reading the sellers’ own lot pages.

Wilton Benítez’s processing is worth spelling out, because “washed with thermal shock” hides a great deal. JBC’s description of his Rume Sudan lot lists selective harvesting, sterilisation of the cherry in ozonated water, UV treatment, thermal shock with hot then cold water, depulping, double anaerobic yeast fermentation in bioreactors, washing, and controlled drying to 10.5% internal humidity.² That is laboratory process control applied to coffee fermentation — Benítez is a chemical engineer by training — and it is a large part of why his lots taste so unlike the eucalyptus-and-jasmine profile the same variety gives at Las Margaritas.²

To verify

The Las Margaritas plot size and the introduction story are single-source and unretrievable. The research report attributes to La Cabra a 4.8-hectare plot of pure Rume Sudan at Las Margaritas that “has consistently produced outstanding results,” plus washed processing in fermentation tanks and mechanical driers giving ginger and lemongrass aromas and a cup of lemon and white tea. It attributes to Xliii Coffee the claim that Café Granja La Esperanza introduced Rume Sudan to Colombia. Both pages returned HTTP 429 and could not be read directly; the farm, region, altitude and processing above are independently confirmed by 43 Factory’s lot page,³ but the plot size and the introduction claim are not.

What it tastes like

There is no calibrated sensory study of Rume Sudan to point at. What exists is the wording sellers use, and across the two Colombian farms it splits cleanly in two directions:

• Botanical and floral — eucalyptus, jasmine, lemon peel at Las Margaritas.³
• Sweet red fruit — red candies, cherry cola, red grape at Granja Paraiso 92; tangerine, grape jam, cherry limeade and strawberry blossom in JBC’s version of the same producer’s lot, which it sums up as “intensely floral.”²⁴

The honest reading is that the second set is telling you as much about Benítez’s fermentation as about the plant. The consistent thread across both — and the thing breeders presumably valued — is an intense floral, botanical character rather than the blackcurrant-and-grapefruit register of Kenyan SL28. See Cupping and Coffee scoring for how cup quality is formally assessed, and note that none of these descriptors came from a calibrated panel.

To verify

Roaster tasting notes not read directly. The research report also cites Queen Bee Coffee (red apple, cherry, blueberry, spiced finish) and Onyx Coffee Lab (jasmine, juniper, white flowers, lemongrass, sometimes eucalyptus, from a La Riviera lot in Colombia). Neither page was fetched, so these are recorded as reported descriptors rather than confirmed ones — and Onyx’s La Riviera is a third Colombian farm growing the variety that this note otherwise has no information about.

To verify

No cupping score, auction price or competition placement for any Rume Sudan lot could be verified. 43 Factory’s page says its beans are evaluated on a “93,5-point scoring system” but does not state that this lot scored 93.5 — confirmed by reading the page.³ That phrasing is easy to misread as a score and should not be quoted as one. No Cup of Excellence, Alliance for Coffee Excellence or Specialty Coffee Association record isolating a Rume Sudan lot was located, and retail prices on seller pages change too often to record. Anything specific would need to come from an auction result or a competition database directly.

Related

• Ruiru 11 · Batian — the Kenyan disease-resistant varieties built on it
• CATIE · CIRAD — the institutes behind Centroamericano, its most direct offspring
• Coffee berry disease — the problem it was collected to solve
• Coffee leaf rust — the other disease its descendants were bred against
• Timor Hybrid — the other great resistance donor, and the Robusta-derived alternative to it
• SL28 · SL34 — its co-parents in the Kenyan crosses, and the cup standard it was blended with
• Bourbon · Typica — the cultivated families whose lost defences it restores
• KALRO — the Kenyan institution whose predecessor ran the breeding programme
• Colombia — where it is now grown as a single variety
• Washed process — how every documented Rume Sudan lot is processed
• Geisha — the other variety whose whole market rests on cup character rather than yield
• Cupping · Coffee scoring — how the flavour claims above would have to be tested

Official links

• (no official website found — World Coffee Research has no standalone catalogue record for Rume Sudan; the nearest authoritative documentation is its entry as a parent in World Coffee Research — Centroamericano)

Footnotes

1. World Coffee Research — Centroamericano ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

2. JBC Coffee Roasters — Wilton Benitez Sudan Rume ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

3. 43 Factory Coffee — Sudan Rume #00046, Colombia ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

4. September Coffee — Wilton Benitez Sudan Rume, Colombia ↩ ↩² ↩³