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ScienceShot: How to Spot Crappy Coffee

Sid is a freelance science journalist.

People who enjoy the most expensive coffee in the world can soon sip without worry: Researchers have come up with a way to tell if their cuppa joe is real or faux. The luxury drink in question—Kopi Luwak—gets its name from the Indonesian words for “coffee” and the Asian palm civet, Paradoxurus hermaphroditus, the catlike creature intimately involved in its production. After a luwak consumes the ripe fruits of the coffee plant (image), it digests the outer flesh of the fruit and then excretes the intact beans, which are then collected, washed (thankfully), fermented, sun-dried, and roasted—a time-consuming process that helps contribute to the beverage’s price tag of between $330 to $500 per kilogram. Such a lucrative product is bound to draw counterfeiters and, indeed, the market is flooded with fakes. So, in a new study, researchers chemically analyzed four different blends of coffee—authentic Kopi Luwak, regular coffee, a 50/50 mix of the two, and a brew of coffee beans that producers had chemically treated in an attempt to simulate mammalian digestion. Of the hundreds of organic substances naturally present in coffee, a handful enabled the team to distinguish Kopi Luwak from the other brews, the researchers report in the Journal of Agricultural and Food Chemistry. Specifically, Kopi Luwak sports higher concentrations of malic acid and citric acid, as well as a higher ratio of inositol to pyroglutamic acid. Although trained experts and aroma-sniffing devices called “electronic noses” can tell the difference between real Kopi Luwak and other blends, the new study is the first to specifically identify the chemicals that characterize the true brew, the researchers say. The technique may even be sensitive enough to distinguish pure Kopi Luwak from versions adulterated with varying percentages of other coffees—which offers some degree of reassurance when your morning mud costs about $15 a cup.

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Posted in Chemistry