Despite high coffee prices, producers are still facing an increasing number of challenges. The rising cost of inputs, such as fertilisers, and labour fees means many are unable to reinvest in their farms, leaving them vulnerable to climate change.
Unpredictable weather patterns threaten global coffee production as we know it. According to a study published in December 2024, prolonged droughts and climbing temperatures affect the flowering of coffee plants in Brazil, the world’s largest producer and exporter of coffee, delaying or hastening the maturation of cherries.
These challenges force producers to find new ways to adapt, seeking to preserve quality and yields to secure income. One possible solution is leveraging advanced processing methods that help improve flavour and quality, especially with overripe cherries typically discarded or sold as lower-quality coffee.
I spoke to Nick Mabey, co-founder and director of Assembly Coffee and Volcano Coffee Works, Dr Fabiana Carvalho, a neuroscientist at the University of Campinas, and Professor Lucas Louzada, Director of Operations and Quality Control, and Ana Luiza Pellicer, co-owner and commercial director at Mió, to learn whether these methods are scalable.
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Climate change is presenting more and more challenges
The impact of the climate crisis has long been prevalent across the Bean Belt. The estimate that up to 50% of current global arabica–growing regions could become unproductive by 2050 has been well-known for some time now, presenting the supply chain with unprecedented challenges.
Although the consequences of climate change are present in almost every producing country, Brazil’s leading position in the global market means the repercussions are significantly more noticeable. Persistently above-average temperatures and below-average rainfall have heavily impacted the country’s coffee cultivation.
Last year, Brazil had its hottest winter in recent decades, caused by the El Niño effect, a combination of intense heat and prolonged drought. Coffee plants are highly sensitive to extreme temperature fluctuations, which alter the chemical compounds and activities inside of the plants and cherries.
“The arabica plant has to adjust its physiology to survive in hostile climate conditions,” says Dr Fabiana Carvalho. She leads the Coffee Sensorium, a project that started in 2017 and researches how extrinsic factors influence the consumption of coffee, and is the Head of Research and Development at Mió, a coffee farm and exporter in Monte Santo de Minas, Brazil.
“The carbon metabolism – known as C3 – of arabica plants works optimally in conditions where average temperatures range between 19 to 23ºC. However, when the average temperature rises above 28 to 30ºC for multiple consecutive weeks, the carbon metabolism switches from C3 to C2, working harder as a survival mechanism,” Fabiana adds.
“At this point, the plants’ metabolism is no longer targeting photosynthesis, but focusing on photorespiration. As an analogy, the plant starts neglecting the coffee fruits and abandons its phenological cycle; they start to focus on survival, so the cherries mature from ripe to overripe very quickly.”
Understanding the ripple effects across the supply chain
While not restricted to Brazil, the impacts of a worsening climate crisis are especially prevalent in the country, given its status as the world’s biggest producer and exporter of coffee.
In some of its major growing regions, average temperatures have consistently hit 30ºC throughout the year, inevitably impeding production yields and quality. Because of Brazil’s role in the global market, persistent supply shortages have driven the C price – the benchmark for international coffee prices – to all-time highs in 2025.
“Supply deficits from origin have put a lot of pressure on the delivery of coffee under contract, finance costs have eroded long positions for roasters, and the backwardation of the market has put a lot of pressure on traders getting coffee to the board, so building long term exposure has become risky,” says Nick Mabey, the co-founder and director of specialty coffee roasters Assembly Coffee and Volcano Coffee Works in London, UK.
“A supply squeeze in almost all market facets is playing into this,” he adds.
On the surface, higher prices sound ideal for coffee producers, who have long grappled with income instability during periods of low C prices. But when factoring in rising costs – from pickers’ wages to the increased costs of fertilisers – the reality is that few farmers are reaping the benefits.
Compounded by the effects of climate change, producers in Brazil and beyond face a stark situation. Unpredictable weather and ongoing market volatility render many of them unable to invest in climate mitigation and adaptation strategies, creating a pervasive cycle of income instability and declining quality and yields.
Is processing innovation a solution?
With average global temperatures expected to rise in the coming years, the coffee industry is likely to experience “ongoing systemic shocks” that increase the risk of quality and yield declines, driving up prices even further.
There are a number of agroforestry practices that producers can implement to mitigate changing climate conditions, such as shade cover and intercropping. However, with increasingly unpredictable weather accelerating or delaying plant maturation, posing a significant risk to stable income, producers must find ways to adapt to global heating that offer more immediate relief.
Advanced and novel processing techniques, such as anaerobic and lactic fermentation, have emerged over the past decade as differentiating factors for producers, allowing them to access new markets. These methods result in unique, interesting flavour profiles that cater to diverse consumer preferences, especially in markets like East Asia and the Middle East, which value exclusivity and unconventional tasting notes.
However, as climate conditions worsen, coffee processing innovation has the potential to become an effective strategy for managing the associated problems. A 2020 study found that using different yeast strains during fermentation can exacerbate and heighten different flavours in coffee, allowing producers to hone in on specific sensory profiles.
But whether deliberate fermentation can improve quality and cup score is a different question. The same research paper concluded that the concentration of certain compounds, namely isoamyl acetate, peaked at 24 hours and then began to steadily decline past this point during fermentation, meaning that controlling total fermentation time is essential.
Can fermentation help improve quality?
As the rapid and eventual overripening of cherries becomes a growing issue in prominent producing countries like Brazil, fermentation emerges as a possible solution.
“We noticed that our coffee plants were under severe stress due to the warmer winter; they were losing leaves quickly,” says Professor Lucas Louzada, the Director of Operations and Quality Control at Mió. “We decided to speed up the harvest; however, we then had to deal with the problem of underripe and overripe cherries.
“The central idea about fermenting overripe cherries came to me when I was preparing a class on coffee drying; I remembered a paper I had written in 2019 about the percentage of water available at each stage of coffee fruits, from harvesting to final drying,” he adds.
Over the last five years, Mió, Assembly Coffee, and the Coffee Sensorium have collaborated on many different projects. During this harvest, the team worked together on three deliberate fermentation techniques based on data-driven protocols focusing on increasing the quality of overripe cherries.
“We decided to implement the research protocols on a larger scale to develop high-end specialty coffees from overripe cherries,” says Ana Luiza Pellicer, co-owner and commercial director at Mió.
They placed one lot, which contained 99% overripe cherries, in an oxygen-free tank at 38°C to undergo carbonic maceration. The yeast fermentation lot, containing 60% overripe cherries, was also placed in oxygen-free tanks and inoculated with yeast to kickstart the fermentation process. The team later added glucose and fructose to assist the process.
The “volcanic” fermentation process, which uses baker’s yeast and oxygen to drive fermentation, was also used. The lot containing 70% overripe cherries was placed in an oxygen-rich environment, formed into small mounds, and inoculated with yeast to begin the fermentation process. All three lots were fermented for 72 hours and dried as natural coffees.
A question of scalability
The climate crisis has exposed the coffee industry’s vulnerability to pests and diseases, falling yields, and price volatility. Therefore, to secure a sustainable future for global production and consumption, there is a clear need to support producers in their risk management strategies.
“The most obvious answer would be to invest in shade cover to cool coffee farms,” Lucas says; however, the transition to agroforestry practices requires access to sufficient resources and support.
Novel coffee processing offers a viable alternative to coping with the impact of changing climate conditions, but scalability remains an issue, especially across different producing countries.
In Kenya, for example, a country also dealing with the climate crisis, the majority of coffee is processed at washing stations, where producers and cooperative members often process their cherries together. Utilising controlled, advanced fermentation in these instances would then require significant investment to implement large-scale structural changes, which would prove difficult.
“Unfortunately, thousands of coffee producers don’t have access to scientists or researchers to solve complex problems in real-time,” Lucas adds. “The next few years will be dedicated to studying the physiology of coffee plants and understanding how extreme weather events can affect coffee cultivation and production worldwide without losing sight of quality and food safety.”
Unpredictable and worsening weather conditions underscore the importance of investing in the sustainable future of coffee production. Although coffee processing innovation doesn’t offer a one-size-fits-all approach, it emphasises the need to find new, creative ways to adapt.
“The global climate is changing and, in turn, changing global coffee production,” Lucas concludes. “But until producers understand how they can be proactive about adapting, starting by halting large-scale deforestation, the situation is set to worsen.”
Enjoyed this? Then read our article on how much we really need to know about experimental processing.
Photo credits: Assembly Coffee, Mió
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