Scientists say 'forgotten' coffee with superior flavour is climate change-proof
A 'forgotten' African species of coffee that grows at higher temperatures could save the coffee industry, scientists believe. Coffea stenophylla from Sierra Leone can tolerate higher temperatures than Arabica, the world's most popular coffee, according to experts. But the species also has a superior flavour, with notes of peach, blackcurrant, mandarin, chocolate, caramel and elderflower syrup. According to professional tasters from Nespresso & Jacobs Douwe Egbert (JDE), its flavour is a bit like 'high-end Arabica'. C. stenophylla, also known as the 'highland coffee of Sierra Leone', is a rare and threatened species that was rediscovered in the wild in the West African country back in 2018. Following the successful round of professional tastings, scientists are hopeful it will soon be grown commercially to 'futureproof' the drink from climate change. The multibillion dollar coffee industry that supplies the likes of Starbucks and Costa is plagued with challenges like extreme weather and pests, as well as warmer temperatures. Worryingly for caffeine addicts, experts had not identified any robust means of protecting coffee farming from the climate crisis before now. The project is led by scientists from the Royal Botanic Gardens, Kew, the University of Greenwich, CIRAD (the French Agricultural Research Centre for International Development) and Sierra Leone 'This is a once in a lifetime scientific discovery stenophylla could ensure the future of high-quality coffee,' said Dr Aaron Davis, head of coffee research at the Royal Botanic Gardens, Kew. 'Future-proofing the coffee supply chain to deal with climate change is vital coffee drives a multibillion dollar global industry, supports the economy of several tropical countries, and provides livelihoods for more than 100 million coffee farmers. 'To find a coffee species that flourishes at higher temperatures and has an excellent flavour is a once in a lifetime scientific discovery this species could be essential for the future of high-quality coffee.' Previously suggested solutions to improving resilience include relocating coffee farming areas and adapting the farming environment but these options are too costly and have negative impacts on livelihoods and communities. There are 124 species of coffee, but the coffee market currently relies on just two for 99 per cent of worldwide coffee consumption Arabica and Robusta, each of which make up 56 per cent and 43 per cent of global production, respectively. Arabica, originating from the highlands of Ethiopia and South Sudan, is a cool-tropical plant with a mean annual temperature requirement of around 190C. But it is vulnerable to increasing global temperatures and 'coffee leaf rust' a fungal disease that has severely impacted coffee plantations in Central and South America. Robusta fares slightly better the species grows at low elevations across much of wet-tropical Africa, requires a mean annual temperature of around 230C and is resistant to certain strains of coffee leaf rust. However, Robusta falls short in its flavour and is widely regarded as inferior to Arabica the reason why the majority of Robusta's production used for instant coffee. Until late 2018, C. stenophylla once widely farmed in Upper West Africa had not been seen in the wild since 1954, and there had been no recorded sensory information for C. stenophylla for 100 years. Today, its use as a crop species is non-existent, and only a few examples exist in coffee research collections. In December 2018, Dr Aaron Davis, head of coffee research at the Royal Botanic Gardens and Dr Jeremy Haggar, Professor of Agroecology at the University of Greenwich) travelled to Sierra Leone. There, they worked with development specialist Daniel Sarmu, to try and locate the species in the wild, by using historical specimens from RBG Kew to provide details of the last known locality of the coffee. After visiting the main target location, they found only a single C. stenophylla plant, but after visiting another forest area further east and after several hours of trekking through dense forest they finally located a healthy population. A small sample of C. stenophylla was brought back to the UK, roasted and then assessed by an expert tasting panel at Union Hand-Roasted Coffee a coffee shop in London in August 2020. Based on protocol of the Specialty Coffee Association, the panel awarded the coffee 80.25 out of 100 defined as a 'speciality score'. To reach 'speciality' status, a coffee needs a score of 80 points or higher. 'Arabica is currently our only speciality coffee species, and so this score, particularly from such a small sample, was surprising and remarkable,' said Jeremy Torz from Union Coffee. After this initial tasting in London, a more substantial sample from Ivory Coast was obtained from the Coffea Biological Resources Center on Reunion Island in the Indian Ocean. The sample was evaluated at CIRAD's sensorial analysis laboratory in Montpellier, France by a panel of judges, and then by coffee experts from companies including JDE, Nespresso and Belco. The 15-strong panel blind tested two Arabica samples (one high quality and one low grade), one high-quality robusta sample and the Ivory Coast C. stenophylla. Judges noted its 'complex flavour profile' with a natural sweetness, medium-high acidity, fruitiness and good body. Desirable tasting notes included peach, blackcurrant, mandarin, honey, light black tea, jasmine, spice, floral, chocolate, caramel, nuts and elderflower syrup similar to a high-quality Arabica. When asked if the stenophylla sample was an Arabica, 81 per cent of the judges said yes (compared to 98 per cent and 44 per cent for the two Arabica samples, and 7 per cent for the robusta sample). Despite the high 'Arabica-like' score for stenophylla, 47 per cent of the judges identified the sample as something new, suggesting 'a market niche' for the rediscovered coffee, according to Royal Botanic Gardens. 'These results provide the first credible sensory evaluation for stenophylla coffee, from which we are able to corroborate historical reports of a superior taste,' said Dr Delphine Mieulet, scientist at CIRAD, who led the tasting. 'The sensory analysis of stenophylla reveals a complex and unusual flavour profile that the judges unanimously found worthy of interest. 'For me, as a breeder, this new species is full of hope and allows us to imagine a bright future for quality coffee, despite climate change.' C. stenophylla is classified on the IUCN Red List of Threatened Species as vulnerable, so the future of the species in the wild will itself need to be 'safeguarded'. Further work is now required to fully evaluate its potential as a climate resilient, high-value crop species and breeding resource, including its drought tolerance and resistance to coffee leaf rust. The scientists now plan to plant C. stenophylla seedlings in Sierra Leone and CIRAD on Reunion Island sometime this year, to assess its potential under different environmental conditions. 'We hope that stenophylla coffee will become a flagship export crop for our beloved Sierra Leone, providing wealth creation for our countrys coffee farmers,' said Daniel Sarmu, development specialist from Sierra Leone. 'It would be wonderful to see this coffee reinstated as part of our cultural heritage.' C. stenophylla also has the potential to be used as a breeding resource, to produce new, climate resilient coffee crops for global consumption, according to the team. The research has been published today in .