samples of whole bean and ground coffee in white bowls and plates on a table
different varieties of ground and unground coffee beans in bowls and plates on a table

Rediscovered Coffee Species Tastes Great, Tolerates Warmth: Study

Cultivating stenophylla, untapped by the coffee industry for the last century, could help farmers cope with the effects of climate change, researchers suggest.

Shawna Williams
Shawna Williams

Shawna was an editor at The Scientist from 2017 through 2022. She holds a bachelor's degree in biochemistry from Colorado College and a graduate certificate and science communication from the University of California, Santa Cruz.

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Coffee has a climate change problem. Arabica, which makes up more than half of what goes into the world’s coffee mugs, grows best from 18–22 °C and is thus vulnerable to rising temperatures. Robusta, while more amenable to warmer climates, is generally considered not to taste as good as Arabica, and it garners lower prices for farmers. 

Now, a research team proposes that a species that hasn’t been commercially cultivated in a century could be a boon to the coffee industry. As the team reported yesterday (April 19) in Nature Plants, the species, stenophylla (Coffea stenophylla), grows at annual mean temperatures of up to about 24.9 ºC and tastes similar to Arabica. 

Stenophylla has not been cultivated since the 1920s, with historical records indicating that it fell out of favor because of poor yields and competition with robusta, the authors write in their paper. It continued to grow in the wild, but until the current study, no sightings had been reported outside of Ivory Coast in decades. 

In late 2018, Aaron Davis of the Royal Botanic Gardens in the UK and his coauthors found stenophylla growing wild in Sierra Leone. After acquiring some beans, they set up a taste test comparing the coffee to Arabica and robusta; 81 percent of the 15-judge panel mistook the stenophylla for Arabica. The authors write in their study that “the judges identified a complex range of tasting notes for stenophylla . . . including those popular or desirable in high-quality Arabica: stone fruit (peach), soft fruits (blackcurrant, mandarin), honey, light black tea, jasmine, spice, floral, chocolate, caramel, nuts, English candy and elderflower syrup.” 

“Being somebody who’s tasted a lot of wild coffees they’re not great, they don’t taste like Arabica so our expectations were pretty low,” Davis tells BBC News. “And we were completely blown away by the fact that this coffee tasted amazing. It has these other attributes related to its climate tolerance: it will grow and crop under much warmer conditions than Arabica coffee.” Davis predicts the species could be cultivated in Sierra Leone and make it into shops in five to seven years. 

“For the longer term, stenophylla provides us with an important resource for breeding a new generation of climate-resilient coffee crop plants, given that it possesses a great flavor and heat tolerance. If the historic reports of resistance to coffee leaf rust and drought tolerance are found to be correct, this would represent further useful assets for coffee plant breeding,” Davis tells Reuters

“I think we’re hugely optimistic for the future that stenophylla can bring,” says Jeremy Torz, cofounder of Union Hand-Roasted Coffee in East London, one of the locations used for the taste test, in remarks to Reuters.