Ruiru 11
A compact Kenyan variety released in 1985 in answer to coffee berry disease. It is a composite: hand-pollinated first-generation seed from a Catimor mother and a complex male parent, sold as a mix of siblings.
In short
Ruiru 11 exists because of one bad year. In 1968 an epidemic of coffee berry disease, a fungus that rots the fruit on the tree, cost Kenya half its production. In the 1970s the research station at Ruiru began breeding for immunity to it, and in 1985 released the variety that carries the station's name.
It is compact, very high yielding and resistant to coffee berry disease. The catalogue rates it highly resistant to leaf rust, though the summary line of the same entry says only tolerant. It is also unusual in what it is: not a fixed variety but a mixture of first-generation hybrid siblings, whose seed has to be produced by hand.
Two parents built for two different jobs
Sourced
The breeders wanted a compact plant suited to dense planting that still had the cup quality of the tall varieties Kenya was known for. No single parent offered both, so they built each half separately.
The male parent is a complex hybrid, assembled over many years of crossing. The catalogue lists what each ancestor was chosen for: resistance to coffee berry disease from Rume Sudan, from Timor Hybrid lines and from K7; cup quality from N39, SL28, SL34 and Bourbon. It is tall.
The female parent is a small number of Catimor lines, among them the one later known as Catimor 129. These supply the compact stature and a second layer of resistance to both rust and berry disease.
How a bag of Ruiru 11 seed comes to exist
Sourced
- Mother plants are pollinated by hand. Pollen from the tall male parent lines is applied manually to the flowers of the compact Catimor mothers.
- The seed is first-generation hybrid seed. The cross brings hybrid vigour, which is where the catalogue locates the variety's high yield.
- Siblings are mixed. The seed from these crosses produces a set of related but not identical plants, which are blended and distributed together. Breeders call this a composite variety.
The catalogue names the consequence: because Ruiru 11 depends on hand pollination, it has been difficult to produce enough seed to meet farmers' demand.
What it changed on a farm
CoffeeHQ explanation
Before a resistant variety existed, growing the SL varieties in Kenya meant spraying fungicide against both berry disease and rust, season after season. A variety that resists both removes much of that cost and labour, and a compact one fits more trees on the same land. The catalogue gives a planting density of 2,000 to 3,000 plants per hectare under the multiple-stem pruning used in Kenya.
The price is in what the plant needs. Its nutrition requirement is rated high, and it is listed as susceptible to nematodes. A variety that yields very heavily and is underfed will not deliver what its ratings describe.
Beside the varieties it was meant to replace, and its successor
Sourced
- SL28 — Tall, low yielding, susceptible to rust and berry disease, and rated exceptional for quality where Ruiru 11 is rated good. The comparison the breeders were working against.
- SL34 — Tall and also rated exceptional, with medium yield and no resistance to either disease. One of the quality ancestors of Ruiru 11's male parent.
- Batian — Released in 2010 from the male parent lines of Ruiru 11. Tall, resistant to berry disease, rated very good, and a mix of pure lines that needs no hand pollination.
- Catimor — The group its mother plants come from, and the source of its compact stature.
The argument about how it tastes
Tendency, not a guarantee
The catalogue rates Ruiru 11 good for quality and SL28 and SL34 exceptional, so on its own ratings there is a gap. Those ratings are not consistent with the stronger claim sometimes made, that Ruiru 11 cannot produce fine coffee: they describe potential at high altitude under good management, and say nothing about any particular lot. CoffeeHQ has read no tasting study that compares them.
Batian is rated very good, one step above Ruiru 11. CoffeeHQ has not tasted either side by side and makes no claim about the difference.
What to do next
- Batian — The tall variety selected from Ruiru 11's male parent.
- F1 hybrids — Why first-generation seed gives more, and why it cannot be saved.
- Kenya — The country whose disease pressure and cooperative system shaped the variety.
- SL28 — The quality benchmark it was bred to approach.
- Become a coffee expert — A structured programme from the plant and its processing to roasting, water and tasting.
Ruiru 11 in the catalogue
- What it is
- First-generation hybrid
- Genetic group
- F1 hybrid, introgressed
- Lineage
- Composite variety made of many varieties. Catimor (female parent) x multicross selection involving K7, SL28, N39, Rume Sudan, among others (male parent).
- Breeder
- Coffee Research Foundation (now Kenya Agricultural and Livestock Research Organization, KALRO)
- Stature
- Dwarf, compact
- Bean size
- Large
- Yield potential
- Very high
- Quality potential at high altitude
- Good
- Coffee leaf rust
- Highly resistant
- Coffee berry disease
- Resistant
- Nematodes
- Susceptible
As recorded in the World Coffee Research variety catalogue, read on 8 October 2026. Each rating is a category the catalogue assigns by comparison with reference varieties, not a measurement, and describes potential under good management. Disease ratings change as diseases evolve, and one confirmed in one country need not hold in another.
Where Ruiru 11 is documented in the atlas
Only countries CoffeeHQ has written an entry for, and only where a document it has read names Ruiru 11 there. This is not a list of everywhere it is grown.
- Kenya. Bred at the coffee research station at Ruiru and released in Kenya in 1985; named in the same 2022 study. Source: Coffee Varieties Catalog: arabica and robusta entries, with the histories of each.