Pre-Ground Coffee Can Contain Corn, Soybeans, Twigs, Dirt

That's the unappetizing news from researchers analyzing java's chemistry.

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No doubt about it: there is trouble in coffee land. Drought and the spread of "leaf rust," a plant disease, has left growers suffering in Brazil, the source of roughly a third of the world's coffee supply.

This one-two punch to the java industry has kicked prices up to their highest point in years and fanned fears of a global shortage (though those worries seem to have been premature). With the future uncertain, some unscrupulous folks in the supply chain have decided to get sneaky. They're increasing profits by padding ground coffee with filler ingredients, say researchers. These adulterants range from relatively harmless things like chicory and brown sugar to more eyebrow-raising stuff like acai berries, soybeans, and peanuts, which could be problematic for those with allergies. And then there's the awful, inedible dreck that winds up in the mix, which we'll get to in a second.

American Chemical Society

Coffee fillers have become visible enough that they've attracted the attention of scientists at Brazil's Universidade Estadual de Londrina, who yesterday announced they've developed a new test to detect non-coffee ingredients. Standard methods now involve peeking at grounds under a microscope or simply tasting the brew; this updated technique, however, uses liquid chromatography and statistical analysis. The researchers believe this way provides a comprehensive view of the coffee's chemical makeup, while removing any potential biases held by human taste-testers.

Team leader Suzana Nixdorf says the procedure is 95 percent accurate in distinguishing foreign fillers like corn, wheat, rice, beans, sugar, and starch syrup. It's also good at picking up on "impurities" that sometimes are combined with ground coffee, whether intentionally or not. She explains a bit more about what form these can take:

These impurities can even be parts of the coffee plants, introduced at harvest, that are not really supposed to be in the final product. Wood, twigs, sticks, parchment, husks, whole coffee berries or even clumps of earth that are almost the same color as coffee have been found. Identifying them is essential because if there is a large amount of impurities, they were probably added purposefully—not by accident, as some producers claim, says Nixdorf.

Needless to say, the test described in Nixdorf's research—which was partly funded by the Brazilian government—is not about to reach home kitchens anytime soon. But if adopted as a common quality-control method in South America and elsewhere, the hope is that it could provide reassurance to consumers worrying that their coffee is tasting too earthy.

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