Coffee (Coffea L.) is the main source of income for around 100 million producers residing primarily in developing communities throughout the Coffee Belt, the majority of whom are smallholder producers growing coffee on plots smaller than a few hectares. Within the last couple of decades, coffee consumption has increased year-on-year, making these producers even more important for the growing demand. Yet, with the recent impacts of climate change, caused primarily by increased temperatures coupled with reduced and less-reliable rainfall, and the spread of coffee leaf rust, coffee farming is facing severe challenges.
Roughly 60% of coffee grown worldwide is Arabica (C. arabica), with the remaining 40% coming from robusta (C. canephora). Arabica is a sensitive species requiring quite specific set temperatures and rainfall during certain times of the year in order to successfully produce fruit and maintain high yields, and quality. The flavor profile of Arabica is considered superior to that of robusta and is preferred by specialty coffee drinkers. However, with climate change and the prevalence and severity of diseases, particularly coffee leaf rust in Central and South America and coffee wilt disease in Africa, coffee producers around the world are facing numerous challenges. In addition, climate change is causing a reduction in the land area suitable for growing both Arabica and robusta, forcing producers to either adapt or diverse away from coffee. On farm adaptation methods, such as increasing shade, mulching and irrigation can be expensive and moving farms to more climatically optimal regions is not possible due to land tenure issues and lack of access to resources. Diversifying away from coffee to other crops, or other alternative livelihoods, could cause a substantial reduction in coffee production which would severely impact the coffee sector as a whole, including the world of specialty coffee.
Drying Liberica coffee (Coffea liberica). Image: Aisyah Faruk (Royal Botanic Gardens, Kew).
Aaron Davis, Senior Research Leader of Crops and Global Change at Royal Botanic Gardens, Kew (UK), argues that we need to substantially diversify the coffee crop portfolio if we are to stand a chance of sustaining the global coffee supply under climate change. High extinction risk for wild coffee species and implications for coffee sector sustainability (science.org)
Davis is a leading expert in wild coffee species, and the future of coffee. Arabica and robusta represent two species of coffee, with Arabica having hundreds of cultivars that are being utilized worldwide. Yet, in total, there are 130 wild coffee species, according to Davis, many of them different to Arabica and robusta.
A mature specimen of Liberica coffee. Image: Aaron Davis (Royal Botanic Gardens, Kew).
Amongst the wild species pool, Davis considers there to be a number of priorities for development, including C. liberica and C. stenophylla, species that were farmed and exported in the latter part of the 19th and early 20th centuries, but which fell out of favor for one reason or another. Both species have been evaluated for sensory quality, and each possess specific climate resiliency attributes. Notable is stenophylla coffee, which has a flavor profile akin to Arabica but grows under a mean temperature range that is 6.2–6.8 °C higher than Arabica, and may have resistance to coffee leaf rust. Arabica-like flavour in a heat-tolerant wild coffee species | Nature Plants. The downside of stenophylla is that its yields are low compared to Arabica, but it has the potential to score above 80 and perhaps into the mid-80s and beyond, in hot, low elevation environments. Liberica coffee was a major commodity species roughly 120 years ago, alongside Arabica, and was favored by producers for high yields and robustness, in addition to its ability to crop in low elevation regions. The major downside was its unfavorable flavor profile, which was one of the reasons for its demise. However, Davis and co-workers, and a growing body of producers, roasters, and baristas, are now challenging this viewpoint, and are finding that some types of Liberica have much to offer from a sensory perspective, with scores approaching 80 points and beyond.
Specialty coffee, according to Davis, has the potential to help popularize the usage of wild coffee species. Consumers of specialty coffee are constantly looking for something new to drink and experiment with, to extend the coffee experience – and a wild (or underutilized) coffee species is just the adventure for these consumers and perhaps for those that do not normally drink coffee. Specialty roasters alike will want to challenge themselves with roasting species other than Arabica, understanding roasting profiles to fit the various shapes, sizes, and densities of the beans. This interest, in addition with the support from large commodity-based companies, will help create a future for new coffees and their producers.
Pulping fruits of stenophylla coffee (Coffea stenophylla). Image: CIRAD.
Many coffee consumers using blends of Arabica and robusta, douse their coffee with milk, and prefer dark roasts. Here, the change will likely only have a small impact for these consumers, as early experimentation suggests that non-traditional species can be used to fill this popular part of the market.
One of the difficulties facing the global coffee growing community will be access to living plant and seeds material (germplasm) of these ‘new’ coffees, due to international protocols preventing the transfer of species to different countries and continents. Coffee science and research are thus essential to guiding dissemination in a legal and equitable fashion. In addition, on-the-ground intervention must be enacted to train and teach producers about these new species.
The leaves of Liberica coffee (Coffea liberica). Image: Aaron Davis (Royal Botanic Gardens, Kew).
There is no immediate end in sight for the dominance of Arabica in the specialty coffee market, but over time it will continue to experience major challenges in our changing world. This has happened in the past with many other crops — for example species of maize and wheat — and the farming landscape for coffee is much more dynamic than most people realize. Over its history, the global coffee farming sector has shown remarkable resilience, but it now needs to prepare itself for its greatest challenge. Underutilized and wild coffee species are likely to play a key role in this future, and hopefully it will not be long before we see some of these coffees offered by roasters, in our cafes and even on our supermarket shelves.