‘Fermented in the gut’: scientists uncover clues about kopi luwak coffee’s unique taste | Coffee

It’s a coffee favored by Hollywood and influencers – now researchers say they’ve found an ingredient that could help explain kopi luwak’s unique flavor.

Also known as civet coffee, kopi luwak is produced from coffee beans that have passed through the digestive system of the Asian civet. The resulting product is not only rare, but also very expensive – costing around £130 for 500g.

It’s also controversial, with animal welfare experts raising concerns that some producers keep civets in battery-like conditions.

Researchers say they have discovered new clues about coffee’s unusual taste, revealing that unroasted beans extracted from civet feces have differences in their fat content compared to those in ripe coffee berries harvested by hand from trees.

“We think the way it is fermented [the] make tripe[s] the profile is different,” said study co-author Dr. Palatty Allesh Sinu from the Central University of Kerala, India. “The enzymes and microbiome involved in fermentation [in the civet] [are] different from [the] manual fermentation process.

Writing in the journal Scientific Reports, Sinu and colleagues reported how, in January 2025, they collected beans from wild civet feces as well as trees in five estates in Karnataka, India, that grew beans. robust coffee.

The team then prepared and ground both groups of beans – although they did not roast them – before analyzing them.

“During roasting, several heat-sensitive oils and esters can be degraded or change their profile,” Sinu said.

While the team noted that some previous studies had shown kopi luwak to have lower protein and caffeine content than traditional coffee – the findings, experts say, are due to the beans passing through the civet’s gastrointestinal tract – no significant differences in protein or caffeine levels were found between the two groups of beans analyzed in the new study.

However, the beans from civet poop had a higher fat content, as well as higher levels of two fatty acid methyl esters – substances based on the building blocks of fat.

The team says the findings could help explain the taste of kopi luwak.

“Fats and oils are essential ingredients in flavored materials,” Sinu said, pointing to many volatile organic compounds — substances that help give aroma and flavor – use fat as a carrier or carrier.

Ramit Mitra, the study’s first author, said the two fatty acid-based substances were commonly used in the food industry as flavoring agents and were likely to impart a milk-like flavor.

“Therefore, we cannot exclude the possibility that these two compounds contribute to the taste profile,” he said.

Researchers note that there are other important factors that affect coffee flavor.

“The basic taste of coffee develops primarily from roasting and the chemical alterations that occur during this process. Our study focuses on examining the raw form,” Mitra said.

Dr Simon Maher, associate professor in sensors and analytical instrumentation at the University of Liverpool, who was not involved in the work, said the study suggested that civet digestion changed the chemical profile of the beans.

“Civet-processed beans showed subtle differences, with higher fat content and more of certain fatty acids that could influence flavor, although the study was based on small samples of unroasted beans,” he said.

“Further research is needed to confirm how much of this substance survives roasting and shows up in sensory tests,” he added.