Your Coffee Maker Is Full Of Mold. Here's How To Clean It.

09/29/2014 04:34 pm ET | Updated Oct 01, 2014
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We love nothing more than a good cup of coffee. But a good cup of mold? Not so energizing.

A 2011 study from NSF International found that about half of coffee makers (we're talking the classic, basket-and-carafe kind here) had yeast and mold growing in their reservoirs. About one in ten were home to coliform bacteria. On average, home coffee reservoirs also had higher germ counts than both bathroom door handles and toilet seats.

And while the study tested only 22 households, germ specialist Kelly Reynolds said she doesn't doubt the results.

"(Coffee makers) are certainly a moist environment where mold and bacteria are known to grow in high numbers," said Reynolds, who studies household germs at the University of Arizona. "Our bodies can deal with them, but at some point they'll grow to levels high enough to cause sickness."

And contrary to what you may believe, hot water isn't enough to get this gunk out. (The advice about running coffee through to disinfect? Not entirely accurate, either.)

We asked Carolyn Forté, director of the Home Appliances and Cleaning Products Lab at the Good Housekeeping Research Institute, about the most effective way to clean your coffee maker. The magic ingredient turns out to be vinegar, which (in addition to sanitizing) "decalcifies," or removes the mineral buildup from tap water.

If you have a classic coffee maker, Forté says to give it a gentle cleaning every day and to decalcify it depending on how hard the water is where you live.

"The carafe, lid and filter basket should be cleaned daily with warm, sudsy water," Forté told The Huffington Post via email. "A coffee maker that's used daily should be decalcified about once per month in hard water areas and every two to three months in soft water areas."

Similar rules apply for "pod-based machines" like Keurigs -- debris can clog their many nooks and crannies, so they also benefit from a vinegar run-through every few months, Forté says.

It really depends on how often you use your coffee maker and for how long it lies dormant. Because mold spores love to grow in nice, moist, quiet environments... or, say, a coffee maker you've left unwashed on your counter over the weekend.

No matter how often you use them, these decalcifying steps (outlined here for classic coffee makers) are the key to better-tasting coffee. And we could all go for some of that.

  1. Fill the coffee maker's water chamber with equal parts white vinegar and water. Using a paper filter, allow to brew until half the chamber is empty.
  2. Turn the coffee maker off and let it sit for 30 minutes, then finish brewing.
  3. Rinse the machine by using a new paper filter to brew a pot of clear water. Do this twice.
  4. Fill the carafe with warm, sudsy water and some rice as a gentle abrasive. Swirl the mixture in the pot, then use a scrubber sponge to remove any gunk. Rinse and dry.
  5. Wipe the outside of the machine with a damp cloth (but remember, this and the previous step should really happen every day).

Voila! Delicious, germ-free coffee!

If you're looking for a fresh start with a sparkling clean machine, check out some of Good Housekeeping's favorite new coffee makers, from single-cups to big-time brewers.

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