The short version. The coffee that comes off the Kasama plateau, ours included, is grown mostly on Catimor 129, Castillo and Java, and the first two names make a certain kind of coffee drinker wince. Catimor is a family of hybrids bred in Portugal from a tree that appeared on the island of Timor in 1927 and should not have existed: a natural cross between arabica and robusta. It was bred for leaf rust resistance, not flavour, and at high altitude the classic varieties usually beat it in the cup. Two things the wincers rarely know: Colombia's coffee is now largely a Catimor descendant called Castillo, and Kenya's celebrated Ruiru 11 has a Catimor mother, from the Catimor 129 line planted at Kasama. At 1,300 to 1,400 metres, with irrigation and a chocolate-forward cup, the plateau is close to where these trees do their best work.
In 1927, on the island of Timor, then a Portuguese colony in the far east of the Indonesian archipelago, somebody noticed a coffee tree growing in a Typica plantation that did not look like the others. It was vigorous, it fruited well, and when leaf rust came through it stayed green.
It was, on later examination, a cross between Coffea arabica and Coffea canephora, the robusta species. The two rarely produce fertile offspring together. This one had.
Why Portugal cared
Coffee leaf rust, Hemileia vastatrix, is the fungus that destroyed Ceylon's coffee industry in the 1870s and turned the island to tea. By the 1950s it had eaten through most of Africa and Asia, and everyone in the trade knew it would reach the Americas eventually.
The Portuguese, who then ran Angola, Mozambique, São Tomé and Timor, set up a research station for the disease at Oeiras outside Lisbon: the Centro de Investigação das Ferrugens do Cafeeiro, the CIFC. In 1958 it received seed from the Timor tree. In 1959 the breeding programme began. The plan was simple to state and slow to execute: take the rust resistance the Timor Hybrid had inherited from its robusta parent and cross it into a compact, productive arabica.
The station picked two Timor Hybrid plants for their rust resistance, accessions CIFC 832/1 and 832/2, and crossed them in 1967 with Red Caturra, CIFC 19/1, a dwarf mutation of Bourbon from Brazil. The crosses were coded HW26 and H46. The offspring were named by portmanteau, Caturra plus Timor, and tested in Angola and Brazil. Rust reached Brazil in 1970. Catimor seed left Oeiras for research stations around the world.
Why specialty coffee turned on it
Catimor did what it was built to do. It resisted rust and coffee berry disease, grew short enough for dense planting, and yielded heavily. Governments and cooperatives from Central America to Vietnam planted it by the million.
What it did not always do was taste good. Mercanta, one of the larger specialty importers, puts the case fairly: at low altitudes there is little sensory difference between Catimor and other arabicas, but above about 1,200 metres Caturra, Bourbon and Catuaí cup better. The complaint from tasters is a harsh, sometimes phenolic edge attributed to the robusta ancestry, most pronounced when the tree is grown high, unshaded or underfed, since Catimor needs careful fertilising and shade to hold quality.
Because specialty coffee prizes high altitude, and because the classic varieties do beat Catimor there, the family acquired a reputation. On a competition table, “Catimor” on the label is a mark against.
That reputation is deserved in the narrow case and wrong in the general one, and the two largest arguments against it are Colombia and Kenya.
Colombia's secret
Colombia's coffee research centre, Cenicafé, began trials with the Timor Hybrid in 1961 and was crossing it with Caturra by 1968. In 1982 it released Variedad Colombia, a five-generation Catimor composite, and in 2005, when rust had evolved past Colombia's resistance, it released Castillo, named for the researcher Jaime Castillo. Castillo is a Caturra-and-Timor descendant. Castillo alone is now around 40 per cent of Colombia's plantings. The Federación Nacional de Cafeteros puts rust-resistant varieties as a class, Castillo and its zonal selections together with Cenicafé 1 and Tabi, at roughly 84 per cent of the planted area. Those two figures get quoted as though they were the same one. They are not: the first is a variety, the second is a category, and the gap between them is the rest of Cenicafé's breeding programme.
So the balanced, caramel, everyday Colombian that half the world thinks of as the definition of a good coffee is, more often than not, a Catimor. The bags do not say so. Castillo has appeared among the winning varieties at Colombia's Cup of Excellence, including the 2021 competition.
Kenya's mother
Kenya is the origin the specialty world treats as the gold standard for acidity and complexity, and its own breeding story runs through the same tree.
In 1968 an epidemic of coffee berry disease destroyed half of Kenya's crop. The Coffee Research Station at Ruiru spent the next seventeen years building a replacement. Ruiru 11, released in 1985, is a deliberate hybrid: a tall, complex male parent bred for cup quality and disease resistance from SL28, SL34, Bourbon, K7, Rume Sudan and Timor lines, crossed onto a compact female parent chosen for dwarf stature and rust resistance. That female parent came from a small number of Catimor lines. One of them, according to World Coffee Research's variety catalogue, was Catimor 129.
Batian, released in 2010 and now the variety Kenya's research institute recommends, was selected from the male side of Ruiru 11 and carries Timor Hybrid parentage of its own.
Catimor 129 is one of the three varieties the Kasama estates list on their profile. The tree that makes specialty drinkers wince is the mother of the tree Kenya is proudest of.
What grows at Kasama
The importer Covoya's profile of Kateshi and Ngoli lists Catimor 129, F6, Castillo and Java, with other trial varieties beside them. Two of those four you now know. The other two deserve a line each.
F6 we have not been able to identify with confidence; it may be an internal estate designation for a sixth-generation selection rather than a named variety. We have asked.
Java is the surprise. It sounds Indonesian and was long assumed to be a Typica selection. Genetic fingerprinting by World Coffee Research showed otherwise: Java is a selection from an Ethiopian landrace population, taken from mother trees in what was then Abyssinia by the Dutch researcher P.J.S. Cramer in 1928, grown on in Java under the name Abyssinia, carried from there to Cameroon, where the line was kept, and from Cameroon to Costa Rica in 1991 by the French agricultural research body CIRAD. It is prized for cup quality and some tolerance to coffee berry disease. So the one variety on the Kasama list with no robusta in it is, genetically, Ethiopian.
Why it works on the plateau
Put the pieces together. Catimor cups poorly when it is grown high, dry and hungry. Kasama sits at 1,300 to 1,400 metres, near the top of the band where Mercanta says the difference from classic varieties is small. The estates are irrigated from dams and reservoirs, which takes the drought stress out, and run as commercial farms with the fertiliser programme the variety needs. And the cup the whole trade describes for Zambia, full body, chocolate, gentle acidity, is the cup Catimor gives when it is happy: it was never going to be a Kenyan, and nobody at Kasama is pretending it is.
The proof is in the competitions. A Ngoli natural won Taste of Harvest in 2019 and placed second across Africa. A Starbucks Reserve buyer chose Isanya for the Seattle Roastery in 2018. Neither competition publishes the variety of the winning lot, so we cannot tell you which tree won. What we can tell you is what the plateau is planted with, and it is mostly Catimor 129, Castillo and Java, judged blind against Kenyan SL28 and Ethiopian landraces.
What we print
One caveat on all of the above. The published variety list for the plateau is the estates', because they are the ones who publish. We buy from smallholders, and if a lot we buy turns out to carry something other than these three, we will print that instead.
We print the varieties. Most roasters selling Zambian coffee do not, and our read of the foreign product pages is that some borrow “Bourbon” or “SL28” from the country's older southern farms to make the bag read better. We are not going to name them, because we have not asked them. A bag that says Catimor 129 and Castillo is telling you the truth about a tree that has fed Colombia for forty years and mothered Kenya's best modern variety. If that makes anyone wince, the cup is the answer.
Catimor, Castillo, Java. Printed on the bag.
Shop the Zambian single origin
More from this series: the origin that died and came back and Kasama, where the coffee grows.
Frequently asked questions
What is Catimor coffee? A family of arabica hybrids bred at Portugal's CIFC from 1959 by crossing Caturra with the Timor Hybrid, a natural arabica-robusta cross found on Timor in 1927. It was bred for resistance to coffee leaf rust.
Is Catimor bad coffee? At high altitude, classic varieties such as Bourbon and SL28 usually cup better. At moderate altitude with good farming the difference is small. Colombia's Castillo and Kenya's Ruiru 11 both descend from Catimor lines.
What varieties grow in Zambia? The main Kasama estates grow Catimor 129, Castillo and Java, with trial plantings. Older farms in the south grow SL28 and Bourbon.
Is Java coffee variety from Indonesia? No. Despite the name, genetic testing shows the Java variety is an Ethiopian landrace selection that passed through Indonesia and Cameroon before reaching Central America.
Sources
World Coffee Research variety catalogue: entries for Ruiru 11 (Catimor 129 as female parent line), Batian, and T8667 (Timor Hybrid origin). Ozone Coffee, “Catimor Coffee Varietal: The Controversial Superhero” (CIFC history, 1958 seed, 1967 crosses). Mercanta, “About Varieties” (altitude and cup notes; Cenicafé timeline). Cafe Imports, “Coffee Variety Glossary” (Catimor and Castillo origin stories). Federación Nacional de Cafeteros, on the share of the planted area under rust-resistant varieties. Alliance for Coffee Excellence, Colombia Cup of Excellence 2021 results (varieties represented). Daily Coffee News, “The Coffee Roaster's Complete Guide to Coffee Varieties and Cultivars,” February 2019. Royal Coffee, “A New World History & Geography of Arabica Coffee Cultivars,” May 2025 (Java and Abyssinia). Daily Coffee News, “A Guide to Indonesian Coffee Cultivars and Varieties,” March 2026 (Cramer, 1928, AB3). Covoya Coffee, “Zambia Estate RFA Natural Top Lot” product page (Kasama varieties, Taste of Harvest 2019). Discover Starbucks Reserve, “Zambia Isanya Estate Coffee,” June 2018.