So how much do you need to worry about germs in your joe? Actually, not too much, says Charles Gerba, PhD, a professor of microbiology and environmental sciences at the University of Arizona, who has conducted several studies on the spread of bacteria and viruses in homes and offices. “I’ve seen data on regular drip coffeemakers and the single-serve types, and they tend to be pretty clean,” he says. “We tested about five different kinds of single-serve coffeemakers, and I didn’t see any issues in terms of bacterial buildup.” Caffeine also has some antibacterial properties, he explains, making it tougher for the bugs to flourish. (Check out what exactly coffee does to your body when you drink it.) MORE: Top 10 Cholesterol-Fighting Foods “The coffeepot handle is more of the problem,” adds Gerba. “We’ve done studies on viruses—we put viruses on doorknobs to see how they travel—and the first place you find them is on coffeepot handles.” But that doesn’t mean you can totally ignore all of your coffeemaker’s innards. Gerba says that we do have to be vigilant about a different kind of microorganism: mold. “A lot of people leave the coffee grounds in the machine, and they stay moist,” Gerba says. “Mold has a better chance of growing in there than bacteria.” You’ve probably seen this in action, too, if you’ve ever left a tiny bit of coffee in your mug over the weekend, and come Monday, it’s dotted with fuzzy splotches. MORE: 8 Things That Happen When You Finally Stop Drinking Diet Soda The best way to keep mold and bacteria at bay is regularly cleaning all removable parts of your coffeemaker in the dishwasher or with soap and water after each use, whether you have a drip machine, a single-serve brewer, a percolator, or a French press. Gerba adds that you should always use paper towels to clean your coffeemaker—not sponges, which can host harmful bacteria like Salmonella and E. coli. In addition, throw out coffee grounds immediately after brewing. And make sure to clean the internal components of the coffeemaker at least once a month, though once a week is ideal. (Use vinegar to clean out your coffeemaker and see what other ways you can put vinegar to use.) This process can be a little different for every appliance, so check the manufacturer’s instructions on how to run cleaning cycles—and enjoy a squeaky clean morning cup.
