Sudan Rume is one of the strangest varieties in specialty coffee. It comes from wild Arabica populations in the Boma Plateau of what is now South Sudan, produces relatively little coffee, and has contributed useful genetics to some important breeding programmes.
It's also the coffee Sasa Sestic used to win the 2015 World Barista Championship. His routine brought Sudan Rume to a much wider audience and helped put carbonic maceration, borrowed from winemaking, firmly on the specialty coffee map.
But the competition story is only one part of it. Sudan Rume had been interesting to coffee breeders for decades before it appeared on a competition stage.
From the Boma Plateau
Sudan Rume traces its history to the Boma Plateau in south-eastern Sudan, in an area that is now part of South Sudan near the Ethiopian border.
In 1941, British botanist A. S. Thomas collected coffee seed from the plateau, including plants from the Rume and Barbuk areas. The material was sent to research stations in East Africa and eventually found its way into international coffee collections. Those collections are the source of the Rume Sudan plants grown today.
The history is worth taking a little care over because “Sudan Rume” isn't necessarily a perfect genetic snapshot of the original wild population. Research comparing surviving Rume Sudan accessions with wild coffee from South Sudan found that some accessions held in gene banks no longer clustered with the South Sudan population. Cross-pollination, dilution and possible mislabelling are all possible explanations.
What remains clear is that the Boma Plateau material represents a valuable and genetically distinctive part of Arabica's history.
Why breeders were interested
Sudan Rume became particularly important because it combines useful agronomic traits with good cup potential.
Its strongest contribution to breeding has been its resistance to Coffee Berry Disease (CBD). Kenyan breeding programmes made extensive use of Rume Sudan as a source of CBD resistance, and its genetics eventually found their way into several important varieties and hybrids.
Centroamericano H1 is the clearest example. It was created by crossing the rust-resistant Sarchimor line T5296 with Rume Sudan. The resulting F1 hybrid combines resistance and productivity with the cup-quality potential contributed by Rume Sudan, and it was released to Central American farmers in 2010.
Ruiru 11 also contains Rume Sudan genetics. It is a much more complicated family tree, involving Catimor as the female parent and a multi-cross male parent that includes K7, SL28, N39 and Rume Sudan among others.
Batian, released in Kenya in 2010, contains Rume Sudan alongside SL28, SL34, N39, K7, SL4 and Timor Hybrid in its broader ancestry.
One common mistake is to put Sudan Rume directly in the family tree of SL28. The two are associated with some of the same Kenyan breeding work, but SL28 itself is a separate Kenyan selection and isn't a Sudan Rume descendant.
Sudan Rume: From Wild Forest to World Stage
South Sudan
Colombia
Seattle
Busan
WBC 2015, Seattle: The Moment Everything Changed
Sasa Sestic's 2015 World Barista Championship win did two things simultaneously: it introduced Sudan Rume to a global specialty audience, and it introduced carbonic maceration, a technique borrowed directly from natural winemaking, to the coffee processing world. The coffee was a washed carbonic maceration Sudan Rume from Finca Las Nubes in Colombia, produced by Camilo Merizalde. Sestic blended it 50/50 with a natural-processed version for his milk course, producing notes of raspberry and white chocolate that judges found extraordinary. Within a few years, terms like "anaerobic," "carbonic maceration," and "lactic fermentation" had become standard vocabulary in specialty coffee. The lot that launched a thousand fermentation methods.
The 2015 World Barista Championship
Sudan Rume had been sitting quietly in research collections and on a handful of farms for decades when it suddenly became one of the most talked-about coffees in the world.
In 2015, Australian barista Sasa Sestic used a Sudan Rume from Colombia, produced by Camilo Merizalde, in his World Barista Championship routine in Seattle.
The coffee was split between two processes: half natural and half washed carbonic maceration. Sestic had been exploring winemaking techniques and how they might be applied to coffee fermentation. The carbonic maceration lot produced the intense fruit character he was looking for, and in the cappuccino he described flavours including raspberry and white chocolate.
He won the competition.
The significance of the moment wasn't simply that Sudan Rume had won a major competition. It showed what could happen when a relatively obscure variety, a producer willing to experiment and a different approach to fermentation all came together.
Carbonic maceration didn't suddenly appear in coffee because of one competition routine, but Sestic's performance gave the technique enormous exposure. Experimental fermentation became much more visible in specialty coffee over the years that followed, with producers experimenting with carbonic maceration, anaerobic fermentation and other controlled fermentation methods.
What does Sudan Rume taste like?
Sudan Rume can be intensely aromatic, but there isn't one fixed flavour profile that defines every coffee carrying the name.
Good lots often have pronounced sweetness and acidity, with floral and fruit characteristics. Depending on the farm and processing, you might find citrus, stone fruit, tropical fruit, berries or herbal and spice notes. Some coffees are remarkably delicate; others have a much more savoury or wine-like character.
Washed Sudan Rume can be particularly transparent, letting the variety's acidity and aromatics come through clearly. Natural processing generally adds weight and pushes the fruit and sweetness further forward.
Carbonic maceration can take things in another direction again. In Sestic's 2015 coffee, it helped create the intense raspberry and confectionery character that became such a memorable part of his routine.
That's one of the things we like about Sudan Rume. There's no single answer to what it tastes like.
Why is Sudan Rume so rare?
For all its appeal, Sudan Rume isn't an obvious commercial choice for a farmer.
It has relatively low yields compared with many modern commercial varieties, which makes the economics of planting large areas difficult. It is also susceptible to coffee leaf rust, despite its useful resistance to Coffee Berry Disease.
The variety is generally associated with high-altitude production, and it is now grown mainly in small quantities by specialist farms. Colombia is particularly associated with Sudan Rume in specialty coffee, with producers such as Café Granja La Esperanza having invested heavily in the variety.
That's a very different role from the one Sudan Rume plays in breeding programmes. As a crop, it's relatively scarce. As a source of useful genetics, its influence is much larger.
A closer look at the plant
Sudan Rume is a relatively compact arabica, although plants can still reach around two metres or more. It produces elongated beans and red cherries when ripe.
Its agronomic value comes less from high productivity than from the combination of genetic diversity, cup quality and useful disease resistance. The original Boma Plateau populations also represent part of the genetic diversity that has become much harder to find in cultivated Arabica.
That matters beyond Sudan Rume itself. Modern cultivated Arabica has a relatively narrow genetic base, which is one reason wild coffee populations are so valuable to researchers and breeders.
Why it still matters
Sudan Rume has an unusual double life in coffee.
On one side, it's a rare specialty coffee that can produce remarkable cups when the right farm, processing and variety all line up. On the other, its genetics have been used in breeding programmes aimed at solving much more practical problems such as Coffee Berry Disease and low productivity.
The 2015 World Barista Championship gave the variety a very public introduction, but its story started much earlier and goes well beyond the competition circuit.
For us, that's what makes Sudan Rume worth knowing. It's a difficult coffee to grow, a fascinating one to taste, and a surprisingly important piece of Arabica's genetic history.
Quick varietal facts
Varietal: Sudan Rume (also Rume Sudan)
Species: Coffea arabica
Origin: Boma Plateau, South Sudan
Collection history: Seed collected from the Boma Plateau in 1941
Genetic background: Distinct wild Arabica population associated with the Boma Plateau; surviving cultivated Rume Sudan accessions do not all perfectly represent the original wild population
Notable breeding contributions: Centroamericano H1, Ruiru 11 and Batian
Optimal altitude: Around 1,700–1,800m
Growth habit: Relatively compact
Cherry colour: Red to dark red when ripe
Bean shape: Large and elongated
Yield: Low
Disease resistance: Strong resistance to Coffee Berry Disease; susceptible to coffee leaf rust
Key growing regions: Colombia and other specialist specialty-coffee farms
Typical cup profile: High sweetness and acidity with floral, citrus, stone fruit, tropical fruit, berry and herbal or spice characteristics; varies considerably with farm and processing
Further reading
World Coffee Research - Centroamericano H1
A useful look at one of Sudan Rume's most important direct breeding relationships: the cross between T5296 and Rume Sudan.
World Coffee Research - Ruiru 11
Detailed information on the complex breeding history of Ruiru 11 and the role of Rume Sudan in its ancestry.
World Coffee Research - Batian
Explains the ancestry of Batian, including Rume Sudan, SL28, SL34, K7, N39, SL4 and Timor Hybrid.
Frontiers in Sustainable Food Systems - Validating South Sudan as a Center of Origin for Coffea arabica
Research into the Boma Plateau coffee populations and the history and genetic identity of Rume Sudan accessions.
Interested in the varieties connected to Sudan Rume? Read our guides to Ruiru 11, Batian, and Centroamericano H1.