As STiR recently reported, coffee farmers in the Cerrado Mineiro region of Brazil reported light frosts in early August 2024. The Cerrado Mineiro region is the second most important coffee-producing region in the country, after Minas Gerais. The frost was light but CPTEC, Brazil’s official forecaster, predicted favorable conditions for more frost and the market response was striking, with coffee pricing surging immediately. This is reminiscent of the devastating frost of 2021 that destroyed hundreds of hectares of coffee crops and is a situation which will be watched closely by the industry worldwide.
But other than the impact on the market, what actually happens to coffee plants when there is a frost? And in a world combating global warming, isn’t a little cold good for coffee?
It’s All Black and White
There are two types of frosts based on their intensities – white and black. White frost is light to moderate, while black frost is very severe. Black frost leads to the death of coffee plants and could necessitate drastic pruning to enable regrowth. Pruning is the practice of cutting branches of the coffee plant, especially the dead and diseased ones, to stimulate the growth of new branches, balance the rate of photosynthesis and respiration, and improve overall plant health.
Frosts in Brazil are a common occurrence and they take place every year. However, in most years, they are mild white frosts and do not cause the death of coffee plants, only inflicting minor damage to the leaves or causing partial burning of coffee cherries. Black frost, in contrast, forms ice crystals that can puncture the plant cells, causing affected parts to turn black and die.
“Frost is a problematic event for coffee farming in Brazil, so much so that on July 18, 1978, a severe black frost decimated all the coffee plantations in Paraná, causing an exodus of over 2.6 million people who were forced to migrate,” explains Professor D.Sc. Lucas Louzada Pereira, the COO at Mió Brazil, Co-founder & President of Mió Institute, and Head of Coffee Design at Ifes-VNI.
Damages and a Long, Hard Recovery
Coffee is a tropical crop, and extreme cold temperatures (below 41° F) are detrimental to the coffee plant’s health. Sub-zero temperatures destroy coffee flower buds, flowers, and fruits while also causing frost burns on the leaves—like frostbite for humans.
In severe cases, it could lead to complete defoliation of coffee plants, and a frost-affected coffee plant can require at least two years to recover. In some cases, it may never recover.
“Areas that have suffered severe damage like total leaf burn are unlikely to produce coffee for two harvests as pruning would be necessary to stimulate the growth of new shoots. In small developing plants, frost freezes the water in the plant’s vessels between the xylem and phloem (plant cells that carry water and nutrients across the plant), causing total death of young plants,” explains Professor Pereira.
“In such cases, it is necessary to replant the entire crop, which could be very expensive for the growers,” he adds.
A new coffee plant could take 4 to 5 years to start bearing decent fruit and up to 7 years to reach maximum production levels.
The Short and Long of the 2024 Frost
In cases of mild frost, like the one recently reported from Brazil, there would likely be a small reduction in coffee supply in the market leading to internal pressure on the prices due to speculation about production. But the long-term picture would be clearer only over time when the damage is fully assessed or if the unaffected crop will make up for the losses from the damaged crop.
With the climate changing rapidly, extreme weather conditions like torrential rains, prolonged droughts, extreme dry spells, and frosts are becoming increasingly common. Frost is only one of the many challenges coffee producers must battle in the course of a growing year.