What is Stenophylla and why is it studied?
Coffea stenophylla is an African coffee species considered nearly extinct since the early 20th century, rediscovered growing wild in Sierra Leone in 2021. It attracts researchers because it tolerates significantly higher temperatures than conventional Arabica — up to 24.9 °C mean annual temperature — while producing a cup quality comparable to specialty Arabica.
Coffea stenophylla is a diploid species native to West Africa, first scientifically described in 1834. It was grown and traded commercially in Sierra Leone, Guinea and Côte d'Ivoire in the late 19th century, before being progressively displaced by Robusta and Arabica cultivation and disappearing from commercial attention in the early 20th century. In 2018, a British research team from the Royal Botanic Gardens, Kew, set out to actively locate it in Sierra Leonean forests; in 2021 they announced finding it growing wild at several forest sites — a scientific rediscovery published in the journal Nature Plants.
The primary interest of Coffea stenophylla for researchers is its exceptional heat tolerance. Comparative climate analyses show that this species grows naturally in zones with mean annual temperatures up to 24.9 °C, whereas commercial Arabica begins to decline in quality above 19–21 °C. Against a backdrop of climate change where Arabica cultivation zones could shrink by 50 % by 2050 according to some projections, Coffea stenophylla represents a major evolutionary pathway — either as a cultivated species in its own right, or as a donor of heat-tolerance genes in crossing programmes.
Organoleptically, the Kew team organised blind tasting sessions with coffee professionals in 2021 and 2022. The results were striking: Coffea stenophylla scored comparably to standard-quality Arabica, with floral, fruity and spiced descriptors. Some tasters even perceived profiles reminiscent of blackcurrant, nutmeg and jasmine. Its caffeine content is moderate, similar to Arabica. A notable historical footnote: a 19th-century French document already described Stenophylla as 'superior' to Libérica and comparable to the finest Arabian coffee — a reputation confirmed 130 years later by scientific blind tests.