Excelsa, liberica and the libex hybrid: coffee's climate-resilient fourth species
Quick read: For years, coffee farmers in Sarawak grew a plant they thought was liberica. In 2026 scientists at the Royal Botanic Gardens, Kew, looked at the DNA and found something else: a natural hybrid of liberica and excelsa they named libex. It is the latest twist in a quiet revolution that began in 2025, when the old catch-all "liberica" was split into three species, with real consequences for a warming coffee world.
Here is a fact to start with. On a set of farms in Sarawak, Malaysia, growers had been tending coffee trees they called liberica for years. When researchers sequenced the DNA, only five plants out of forty-five turned out to be the real thing. The rest were something nobody had bothered to name.
The plant hiding in plain sight
The story broke in 2026, when a team at the Royal Botanic Gardens, Kew, led by the coffee scientist Aaron Davis, published a paper in Scientific Reports proposing a formal name for those mystery trees: Coffea x libex, a natural cross between liberica and excelsa. The numbers were striking. Of 45 Sarawak accessions labelled liberica, 40 carried measurable excelsa ancestry, 28 of them above 12 percent. Only five were pure liberica.
And Sarawak was not alone. The same hybrid, the researchers noted, had quietly turned up across parts of Southeast Asia, India and Central America, grown for generations under the wrong name. It is a rare thing in agriculture: a crop that has been domesticated by accident, its true identity revealed only when someone finally ran the genetics.
How liberica became three
To understand libex, you have to rewind to 2025. That year, Davis and colleagues published a separate study in Nature Plants that quietly rewrote the family tree. Using 353 nuclear genes across 55 accessions, they showed that what the world lumped together as "liberica" was in fact three distinct species: Coffea liberica, Coffea dewevrei (the coffee sold as excelsa) and Coffea klainei, a long-overlooked plant brought back from taxonomic limbo. The count of recognised coffee species rose to 133.
This matters because each species carries its own toolkit. Excelsa, native to Central Africa, grows more like a tree than a shrub, with deep roots and big leaves, and it is described as the more drought tolerant of the group, happy on lower rainfall. In an industry watching its arabica heartlands grow hotter and drier, those traits read like a survival manual.
The surprise in the cup
You might expect a hardy, neglected species to taste like punishment. It does not. Roasters who have worked with excelsa describe bright, layered acidity, notes of stone fruit and dark berries, a streak of tamarind, sometimes a wine-like character, all sitting on a deep sweetness with a long, structured finish. People keep reaching for the same comparison: it drinks closer to a competition coffee than a commodity one.
That reputation is slowly turning into trade. The South India Coffee Company first introduced excelsa to UK specialty roasters back in 2018, framing it as a climate-resilient specialty coffee. The company says it sold more than four tonnes of green coffee in 2025 and expects up to five tonnes in 2026, with requests pouring in for more than 4,000 saplings. Tiny numbers in a global market measured in millions of bags, but the direction of travel is unmistakable.
Why a hybrid could matter most
Libex may be the most interesting character of all, because hybrids can blend the best of both parents. According to the Kew team, the libex cross yields more than liberica, and its thin pulp and parchment make processing more efficient. Best of all for roasters, its bean size sits close to arabica, so the grinder and roast settings barely need to change. The researchers argue it could broaden the climate envelope for coffee farming and carry useful disease resistance, all without a slow, expensive breeding programme, because nature ran the experiment already.
None of this means arabica is going anywhere soon. It still rules the cup, and will for a long time. But the discovery widens the field of options at exactly the moment the industry needs them.
What to do with all this
For a curious drinker, the takeaway is an invitation, not a homework assignment. If you spot an excelsa or a documented liberica lot on a roaster's shelf, buy it and pay attention. You are tasting a species most coffee lovers will never knowingly try, and quite possibly a small piece of how your morning cup survives the next few decades. The coffee world has always been bigger than two names. In 2026, the science finally caught up with the farmers who knew it all along.
Frequently asked questions
What is the difference between liberica and excelsa coffee?
Liberica (Coffea liberica) and excelsa (Coffea dewevrei) are now treated as two separate species, after excelsa spent decades classified as a mere variety of liberica. A 2025 Nature Plants study led by Aaron Davis at the Royal Botanic Gardens, Kew, used 353 nuclear genes across 55 accessions to confirm the split and reinstate a third species, Coffea klainei. Excelsa is described as more drought tolerant and suited to lower rainfall than liberica.
What is libex coffee?
Libex is a natural hybrid of liberica and excelsa, given the formal name Coffea x libex by Royal Botanic Gardens, Kew researchers in a 2026 Scientific Reports paper. Growers in Sarawak, Malaysia, along with parts of Southeast Asia, India and Central America, had been cultivating it for years without identifying it. It yields more than liberica, has thin pulp and parchment that make processing efficient, and a bean size close to arabica.
Does excelsa coffee actually taste good?
When grown and processed well, excelsa is anything but bland. Tasters describe bright, layered acidity with stone fruit, dark berries, tamarind and a wine-like character, plus a deep sweetness and a long, structured finish that can feel closer to a competition coffee than a commodity. It remains rare, accounting for well under 1 percent of world production, so it mostly appears as experimental specialty lots.
Keep exploring
Want to dig into the species, varieties and terroirs behind your cup? Browse the expertcafe.be glossary and buying guides, or work through our frequently asked questions on origins and coffee genetics. This story sits right next to our piece on F1 hybrids and climate-ready arabica.