Some coffee drinkers pooh-pooh the exotic and expensive coffee that comes from the Asian palm civet's poop, but it has become a tempting target for fraud. And there has been no standard test to determine whether products labeled as civet coffee, sold for $150-$227 a pound, are the real thing.
Now, scientists say they have developed a way to authenticate civet coffee, according to a study published online July 27 in the American Chemical Society's Journal of Agricultural and Food Chemistry.
The making of authentic civet coffee begins in fields in countries such as Indonesia, where the small mammals pick ripe coffee cherries. They digest the soft fruit surrounding the beans and excrete the beans, which are then cleaned, wet-fermented, sun-dried and roasted. The coffee is sold in stores in Southeast Asia and is available online.
Scientists have found what they call a "metabolic fingerprint" that allows them to verify "real Kopi Luwak" (Indonesian for "civet coffee") using metabolomics technology, Eiichiro Fukusaki, a corresponding author of the study, says in an e-mail. The unique chemical fingerprint reflects higher levels of citric acid and malic acid as well as a certain inositol/pyroglutamic acid ratio.
Metabolomics is research that focuses on metabolites, which are substances produced during metabolism (chemical processes such as digestion). A metabolic fingerprint consists of metabolites that can be detected by gas chromatography and mass spectrometry.
Fukusaki, a professor in the biotechnology department at Osaka University in Japan, says the method of authenticating the coffee by its fingerprint could eventually be widely used, but technical improvements would first be needed.
Stanley Segall, a spokesman for the not-for-profit Institute of Food Technologists, a scientific society based in Chicago, says the study is a "very good beginning" but more research is needed.
"It's the first study of this type, and it's not clear to me that they were really rigorous in terms of sample selection," says Segall, who was not involved in the study. It would have been useful if they had compared two sets of coffee cherries from the same tree, with one passing through the civet and the other not going through the animal, to see if there was a fingerprint difference between the two treatments, he adds.
It would have been interesting to contrast the scientific analysis with cupping, or tasting, data, says Segall, professor emeritus of nutritional biochemistry at Drexel University in Philadelphia.
Although some sellers claim that enzymes in the civet's stomach break down proteins in the beans, resulting in smoother coffee, Segall says it's open to question whether the animal's digestive process affects flavor.
A difference in taste may be more related to the selection of coffee cherries.
The civet picks the ripest coffee cherries because it wants to eat them, says Rocky Rhodes, president of International Coffee Consulting, based in Simi Valley, Calif. A low-paid farmworker who is having a bad day may not be as consistent in picking ripe cherries, he adds.
Using beans taken from the civet's feces is not associated with health concerns, he says. "If anything, I would say it would be less risky coffee health-wise, because I don't think the civet is going to consume anything that smells like bad fertilizer when it has lots of cherries to choose from."
Although the study found that civet coffee has higher concentrations of certain acids than conventional coffee, those components may not necessarily affect flavor, Rhodes says.
He has tasted several civet coffees, and says a coffee's flavor depends on the selection of coffee cherries and the handling of the coffee through various stages, including roasting.
The story behind civet coffee is what is appealing, he says. "The unique processing, rare nature and mystery of the coffee have been causing the price increase. There is the 'eww' factor for some people; there is the 'wow' factor for others."