Hibiscus, orange and butterscotch in our washed lot from Finca La Palestina. Jasmine, honeysuckle and bergamot in other Peruvian lots, often with a light, tea-like body. That's SL9, also sold as Inca Gesha, and the name on the bag is only the start of the puzzle.
SL9 is an unusual name to find on a bag of Peruvian coffee. The “SL” prefix usually points to Kenya's Scott Agricultural Laboratories, the research station behind varieties such as SL28 and SL34. SL9 was a selection from the same programme, and historical records say it was never distributed.
Then genetic testing linked coffee trees in Peru, commonly known as Inca Gesha, to the same genetic reference. That raised an obvious question: how did a coffee associated with a long-forgotten Kenyan selection end up in Peru? At the moment, nobody can answer that with certainty.
What does “SL” mean?
The SL varieties were selected by the Scott Agricultural Laboratories in Kenya during the 1930s. Researchers examined individual coffee trees from different populations, looking for plants with useful combinations of productivity, quality and other agronomic characteristics.
Each selected tree was given an SL number. Some became commercially important, with SL28 and SL34 the obvious examples. Many of the other selections disappeared from widespread cultivation.
SL9 never made it into commercial use. In a 1956 Coffee Board of Kenya bulletin, P. A. Jones describes it as coming from a block of unknown origin. It was reported to produce heavy crops of good quality at middle altitudes, but its lack of resistance to rust and its susceptibility to coffee berry disease meant it was never distributed. That history is what makes the modern Peruvian material so puzzling.
From Kenya to Peru?
First, what the DNA testing showed. Lance Schnorenberg of Sey Coffee collected leaves from a Peruvian tree the farmer called Inca Gesha and sent them to Christophe Montagnon at RD2 Vision. Christopher Feran's investigation sets out the result. Elsewhere the same trees have been grown and sold as Gesha Inca and Gesha Inka.
The report placed the sample in the “Ethiopian Legacy” genetic group, the southern Ethiopian group linked to arabica's domestication, and found it very close to the SL9 reference sample. It was nowhere near Gesha.
The wording needs care here. The tests suggest the Peruvian trees may be the same genetic material as SL9. They don't prove that a Kenyan SL9 plant was physically transported to Peru, and there's no documented seed trail connecting the original Scott Laboratories selection with the trees now growing in the Peruvian Andes.
So what is growing in Peru?
The name Inca Gesha predates the genetic testing. Farmers and buyers used it because the coffee looked and tasted similar to Gesha, and the name became established locally.
Once the DNA results became known, some exporters and roasters began using SL9 instead. That makes sense for genetic identification, but it gives the trees the name of a Kenyan selection without any evidence that the Peruvian plants travelled through Kenya.
Feran argues that even if the Peruvian trees turn out to share SL9's genetic background, it may make more sense to regard Inca Gesha as a locally established coffee population in its own right, called by the name the people who grow it gave it. The name reflects where the coffee is grown and how farmers came to know it. The genetic label answers a different question.
How could it have arrived in Peru?
There isn't a single accepted explanation. Several have been proposed.
The Tingo María route
Between October 1964 and January 1965, a United Nations Food and Agriculture Organization mission collected coffee seed across Ethiopia. In 1965, 455 of the resulting seedlings were sent to Peru's Tingo María research station, and about 434 were still alive a year later.
Sendero Luminoso attacked the station several times between 1984 and 1988, and records covering more than 50 years of experiments were lost, leaving major gaps in the history of the plants grown there. Ethiopian-derived material from this programme may have found its way into farmers' fields and been propagated for generations without keeping its original name.
The Columnaris possibility
Another theory involves Columnaris, a variety that appears in the Scott Laboratories trials and shares some characteristics with the material now called SL9. The 1956 bulletin describes SL9's young leaves as copper-coloured, a trait Columnaris shares.
Columnaris has a complicated history of its own. It was selected in Java in the late 1880s, on the Pantjoer estate, and was among the first varieties in the Scott Laboratories trials. Feran raises the possibility that some of the coffee now called SL9 could trace back to this material rather than to the specific Scott Labs SL9 tree. Montagnon told him the hypothesis is possible.
Older introductions
Coffee had reached Peru well before the twentieth-century research programmes, and varieties moved between colonial territories, plantations and research stations over many years. Montagnon has suggested that SL-type material may have existed unnamed in Yemen, and could have reached Peru by way of India or East Africa, staying unrecognised until much later.
A more recent Central American route
Feran's 2026 update adds another account from Inkawasi, in Cusco. The story there is that a producer's brother brought seeds back from a monastery in 2011, and the trees went on to win a competition in 2014. Another version dates the introduction to 1996, and the family that owned the tree has said it came from Central America in the 1990s. None of this is established either. It's another possible route in a story where the documentary trail is incomplete.
A new clue from Kenya
London roaster Scenery Coffee has added a data point of its own. In 2019, Alex, now Scenery's co-founder and head of coffee, travelled to Kenya on a sourcing trip with a previous employer. After visiting a dry mill, he asked for some Mbuni, the tree-dried cherries picked at the end of the season and sold on the internal market, to bring home as a training aid.
On a punt, the team germinated some of those cherries. Two out of 50 made it past the cotyledon leaf stage, and Alex kept one. Seven years later that tree is still alive in the Scenery café, and it has produced a 500g harvest of cherries that were processed and cupped at an event in Manchester in 2025. When a leaf sample was sent for genetic testing, it came back as SL9.
One tree and one result don't establish the distribution history of SL9. As Scenery puts it, though, it's at least one data point for SL9 still being cultivated in Kenya, which is notable for a variety with a reputation for being effectively lost.
What does SL9 taste like?
The Peruvian coffees sold as SL9 or Inca Gesha can be intensely aromatic, in a style that helps explain why the Gesha name caught on.
Floral notes are common, with jasmine, honeysuckle and bergamot appearing in descriptions of different lots. Fruit ranges from citrus and stone fruit to tropical flavours such as passionfruit and lychee. Our La Palestina lot shows hibiscus, orange and butterscotch, with a hint of mango. The mouthfeel is often light and tea-like, with pronounced acidity and plenty of sweetness.
None of that is a guaranteed varietal fingerprint. The coffees come from different farms, elevations and processing methods, and the genetic identity is still being investigated. The resemblance to the best washed Ethiopian coffees and some Gesha lots is hard to miss, though.
Where is it grown in Peru?
The best-known Inca Gesha and SL9 coffees come from high-altitude farms. One cluster is around the Inkawasi Valley in La Convención, Cusco, where members of the Incahuasi cooperative grow it at around 2,200 metres. Albino Ibias and his son Saulo at Finca Tres Cedros are among the producers who have brought it to international buyers.
There's also growing interest in the variety in Jaén, Cajamarca, in northern Peru. Our first SL9 comes from Finca La Palestina in the San José del Alto district, where the Alarcón Coronel family works with exporter Origin Coffee Lab on renovation and the introduction of newer varieties.
Our first SL9: Peru La Palestina Washed
José Alarcón and Zobeida Coronel bought the land at La Palestina in 1976, and three generations of the family now live on the farm. The 11-hectare farm is split into seven parcels and grows Geisha, SL9 and Bourbon Marshell at elevations from 1,200 to 2,000 metres. The family processes its washed coffees at a shared wet mill. The farm placed in the top 20 of Peru's Cup of Excellence in 2019, and a Geisha lot came fourth with 90.15 points in the 2022 Cajamarca competition.
We bought this coffee the way we'd hope to buy any variety, by tasting it first. The floral character and fruit stood out on the cupping table, and the questions about what the coffee actually was came afterwards. The name is still being worked out, but the coffee doesn't need to wait. It's sold out now, but you can read about it in our coffee archive.
SL9 or Inca Gesha?
For now, we'd treat both names with a little caution. SL9 is useful because it reflects the genetic testing and gives buyers a way to connect the Peruvian material with a historical reference sample. Inca Gesha is useful because it describes the coffee as it has actually been grown and known in Peru. Neither name completely explains the origin of the trees.
That's likely to stay the case until researchers can match the living Peruvian plants with better-documented reference material and, ideally, find some record of how that material travelled. At Tingo María, the records that might have helped were lost in the attacks of the 1980s.
Quick varietal facts
Varietal: SL9, often marketed in Peru as Inca Gesha or Gesha Inca
Species: Coffea arabica
Historical reference: A selection made at Scott Agricultural Laboratories, Kenya, in the 1930s, from a block of unknown origin
Peruvian identity: Genetically very close to the SL9 reference material, but the historical connection has not been proven
Genetic group: Ethiopian Legacy, according to RD2 Vision's testing; exact identity and relationship to the original SL9 selection remain under investigation
Young leaves: Copper-coloured, according to the 1956 Coffee Board of Kenya bulletin
Yield: The same bulletin describes heavy crops of good quality at middle altitudes
Disease resistance: Poor; the bulletin reports a lack of rust resistance and susceptibility to coffee berry disease
Key growing regions: Peru, particularly Cusco and Cajamarca
Common processing: Washed, with natural and other experimental processes also used
Typical cup profile: Floral and tea-like, with jasmine, honeysuckle, bergamot, citrus and tropical fruit; pronounced acidity and high sweetness
Further reading
Christopher Feran: The Lost Origins of “Inca Gesha”
The most detailed examination we've found of the genetic testing, the 1956 Kenyan bulletin, the Tingo María story and the competing theories, including his 2026 update from Cusco.
Scenery Coffee: Peru Wilber Tello's SL9
An Inkawasi SL9 release with another piece of the story: the genetic test on a tree grown from Kenyan Mbuni cherries.
Montagnon et al.: Deciphering Early Movements and Domestication of Coffea arabica
The 2022 study behind the “Ethiopian Legacy” group, which places the SL9 reference sample alongside other Kenyan selections. Free to read.
Ozone Coffee: The Alarcón Coronel Family, La Palestina, Peru
Our producer profile for the family behind our first SL9, including the farm's parcels, varieties and work with Origin Coffee Lab.
Want to read about the varieties connected to this story? Try our guides to Geisha, SL34 and Sudan Rume.