Diseases and pests in coffee become more frequent and more serious with rising temperatures, according to our partner The Conversation.
Cultivated in West Africa until the beginning of the 20th century, Coffea stenophylla is a “forgotten” variety but much more resistant to heat.
The analysis of this discovery was carried out by Aaron P. Davis, research director in plant resources at the Royal Botanical Gardens of Kew (United Kingdom) and Delphine Mieulet, agronomy researcher at CIRAD (France).
The world is crazy about coffee.
Specifically, he loves arabica coffee.
From the smell of its freshly ground beans to the last sip, it is simply a delight for the senses.
Robusta, which is the other most common coffee species, is almost as traded as arabica, but much less flavorful.
It is also mainly used to make instant coffee or to make blends, while arabica is the preserve of demanding baristas and expensive espressos.
Consumers may be happy, but climate change is making coffee growers bitter.
Diseases and parasites become more frequent and more serious with rising temperatures.
The fungal infection known as coffee leaf rust has devastated plantations in Central and South America.
And while robusta crops tend to be hardier, they need a lot of rain - a tall order as droughts proliferate.
A man picks coffee cherries from a tree © Reynold Sumayku / Alamy (via The Conversation)
This threatening context announces a rather gloomy future for coffee growing.
One of the most promising solutions is to develop new, more resilient coffee crops, which will not only have to tolerate higher temperatures and less predictable rainfall, but also continue to meet consumer expectations for taste and flavor. odour.
Finding the perfect combination of characteristics in a new species seemed unlikely.
But in recently published research, my colleagues and I reveal a little-known wild coffee species ... that looks the most promising yet.
Growing coffee in a warmed world
Coffea stenophylla was first described in 1834 in Sierra Leone.
It was cultivated in the wetter parts of upper West Africa until the beginning of the 20th century, when it was replaced by the newly discovered and more productive Robusta.
It was largely forgotten by the coffee industry.
It nevertheless continued to grow wild in the humid forests of Guinea, Sierra Leone and Côte d'Ivoire, where it was subsequently threatened by deforestation.
Coffea stenophylla, cultivated in the Trinidad Botanical Garden around 1900 © Royal Botanic Gardens, Kew UK (via The Conversation)
We found her trail at the end of 2018 in Sierra Leone after searching for her for years.
But we couldn't find any fruiting trees until mid-2020, when a 10g sample was collected for tasting.
Already in the 19th century, botanists proclaimed the superior flavor of stenophylla coffee, and had identified its good resistance to coffee leaf rust and drought. These first tasters were however often inexperienced, so we had little time to wait before tasting it for the first time in the summer of 2020. But from the first sips, tasted with five other coffee experts, it was a revelation for us. … It was like expecting vinegar and being served champagne!
This first tasting in London was followed by an in-depth evaluation of the flavors of this coffee in the south of France, led by my research colleague Delphine Mieulet.
It brought together 18 coffee connoisseurs for a blind tasting.
They described a complex profile, with natural sweetness, medium-high acidity, fruity taste and good body.
In short, what can be expected from a high quality arabica.
Stenophylla coffee plant growing in the wild, in Côte d'Ivoire © E. Couturon / IRD (via The Conversation)
In fact, this cafe seemed very close to arabica. At the London tasting, the sample from Sierra Leone was compared to the arabica from Rwanda. During the blind French tasting, most judges (81%) said that stenophylla tasted the same as arabica, compared to 98% and 44% for two control samples of arabica, and 7% for a sample of robusta.
The tasters noted notes of peach, blackcurrant, tangerine, honey, light black tea, jasmine, chocolate, caramel and elderflower syrup.
In short, stenophylla coffee is pure delight.
And although it scored highly for its resemblance to arabica, the stenophylla coffee sample was also identified as quite unique by 47% of the judges.
This means that there may be a new market niche for this rediscovered coffee.
The testers approved the sweet and fruity flavor of stenophylla © Cirad (via The Conversation)
New lands to explore
So far, no other species of wild coffee has managed to come close in the quality flavors of arabica.
From a scientific point of view, the results are convincing, as it was quite surprising that stenophylla tasted the same as arabica.
These two species are not closely related, they are native to opposite sides of the African continent and the climates in which they grow are very different.
They don't look alike either: stenophylla has dark fruits and more complex flowers than arabica cherries, which are red.
The white flowers of the stenophylla coffee tree © Royal Botanic Gardens, Kew UK (via The Conversation)
Premium coffee has always been considered to be the preserve of Arabica - native to the forests of Ethiopia and South Sudan - and especially when grown at altitudes above 1,500 meters, where the climate is cooler and better light.
The stenophylla calls this idea into question.
Endemic to Guinea, Sierra Leone and Côte d'Ivoire, it grows in warm conditions at low altitudes.
Specifically, at an average annual temperature of 24.9 ° C - 1.9 ° C higher than Robusta and up to 6.8 ° C higher than Arabica.
Stenophylla also appears to be more drought tolerant, and potentially able to grow with less rainfall than arabica.
Robusta coffee can grow under conditions similar to stenophylla, but farmers are paid half the price of arabica.
This new species would therefore be a way to grow superior tasting coffee in much warmer climates.
And although these trees produce less fruit than arabica, their yield is still sufficient to be commercially viable.
Stenophylla harvest on Reunion Island © IRD / Cirad (via The Conversation)
To select the coffee trees of the future, we need species with great flavor and high tolerance to heat.
Crossing stenophylla with arabica or robusta could make these two varieties more resistant to climate change and even improve their taste, in the case of robusta.
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This analysis was written by Aaron P. Davis, research director in plant resources at the Royal Botanical Gardens of Kew (United Kingdom) and Delphine Mieulet, agronomy researcher at CIRAD (France).
The original article was published on The Conversation website.
Declaration of interests
- Aaron P Davis received research funding from Darwin Initiative (UK).
- Delphine Mieulet does not work, does not advise, does not own shares, does not receive funds from an organization that could benefit from this article, and has not declared any affiliation other than her research organization.
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Drought
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