Surprising ingredients could be lurking in your morning mug. We asked experts to explain.

For a beverage whose devotees are called junkies, coffee has managed to earn a reputation as a veritable health food: In recent years, studies have found that coffee can do everything from boost your mood and sharpen your brain to reduce the risk of type 2 diabetes, Parkinson’s disease and certain cancers. A new Boston University study even found that drinking coffee can help protect your teeth from periodontal disease. 

But according to new research presented at the 248th National Meeting & Exposition of the American Chemical Society, there may be reason to call your cup of Joe into question. Researchers studied ground coffee and found additives like corn, barley, wheat, soybeans, rye, acai seeds, brown sugar and even twigs and sticks in the mixes. They say coffee suppliers are adding these fillers to combat drought-related shortages, particularly in regions like South America.
According to Emma Bladyka, coffee science manager at the Specialty Coffee Association of America, it’s actually normal for roasters to find things like stones and sticks in coffee shipments. “After the beans are picked, they’re spread out on large surfaces like a patio or tarp to be dried in the sun,” she says. “Because they’re exposed to the elements, it’s not uncommon to find things from the earth in the bag.” As for the other fillers, roasters in the U.S. usually catch them when the shipments arrive—they use magnets and other filters to sort out any unwanted objects. Brazilian researchers are also working on a new way to test for coffee impurities that they say will be 95 percent accurate.
Decaf coffee has also been criticized over the years because of concerns about the chemicals used to remove the caffeine. Coffee is decaffeinated in one of four ways: using chemical solvents such as methylene chloride and ethyl acetate, carbon dioxide, or water (also known as the Swiss Water Process).
Certain purists like Dave Asprey, founder of Bulletproof coffee, argue that it’s best to stay away from decaf coffee that’s made with chemical solvents. “The chemicals may not kill you,” he says. But he cites symptoms like headaches, brain fog, and stomach issues as reasons to steer clear.
His M.O.: Sip regular coffee, and limit the caffeine by sticking to a small cup. Otherwise, look for decaf coffee brands that say they’ve been made using the Swiss Water Process.
But Bladyka says all of these methods are safe—even those that involve chemical solvents. “The FDA has approved these compounds for decaffeination and has set limits on the amount of allowable chemical residue,” she explains. “Most blends have less than one part per million, which is not cause for concern.”

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