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Coffee quality is tied to ripeness, and to ensure the highest quality, coffee farmers try to pick cherries at their peak ripeness. But in countries like Brazil, mechanized harvesting is becoming more common, with machines stripping entire trees of fruit. This means ripe and underripe cherries often get mixed together, which negatively impacts quality.
But what if there was a way to process underripe cherries so they taste as good—if not better than—perfectly ripe ones? A recent study found that fermentation might hold the answer.
A group of researchers at Brazil’s Federal University of Uberlândia experimented with fermentation methods to improve the quality of underripe coffee cherries. Their methods took underripe coffees up to a quality level comparable to specialty coffee standards.
For the study, published in the journal Food and Bioprocess Technology, researchers used self-induced anaerobic fermentation (SIAF) to process a mix of ripe and underripe cherries. SIAF is a technique that involves sealing cherries in an airtight environment to kick off the fermentation process (without removing oxygen—the fruit produces carbon dioxide, displacing oxygen). Cherries were hermetically sealed in 200-liter barrels for up to 96 hours after harvesting. The researchers added microorganisms to inoculate certain batches.
Specifically, the researchers looked at samples of the Arara variety, a disease-resistant coffee variety developed in Brazil. Arara has been popular among farmers for its productivity and cup quality.
When Q graders evaluated the processed samples, the findings defied expectations. Both ripe and underripe coffees scored above 80, the threshold to be considered specialty grade. In some cases, the underripe lots scored higher than the ripe ones.
“Contrary to the conventional view that immature beans are detrimental to coffee quality, results revealed that, under controlled fermentation conditions, immature beans can enhance the sensory characteristics of the beverage, resulting in profiles comparable to or even superior to those of coffees made exclusively from mature beans,” the authors wrote.
Read the full story on how fermentation can transform coffee from Daily Coffee News here.
Photo by Nathan Dumlao on Unsplash
