Clouds in your coffee? Uh, no that’s bacteria

Isn’t it just great that science is validating your love of drinking coffee?

After all, we’re learning that coffee can can help you live longer, cut your risk of some cancers as much as 50 percent and help stave of Alzheimer’s and Parkinson’s disease.

Of course, you may want to be careful about limiting the amount of cream and sugar you add to your morning cup of coffee. Or maybe you drink it black. But regardless, there’s a big chance you’re getting more than you’ve bargained for in every cup… but if you’re not careful, it might not be all good.

Coffeemakers can be a source of more than hot beverages that help you wake up in the morning. They may be harboring pathogens capable of making you sick.

The microorganisms that may lurk in coffeemakers include a wide range of bugs that can cause illness. If you’re not scrupulous about keeping these machines cleaned out, you may be in for some unwelcome surprises in your coffee cup.

report at, shows that one-cup coffee makers can be the home to nasty bugs like staphylococcus, streptococcus and bacillus cereus, E. coli and other bacteria that originate in the human intestinal tract.

One coffeemaker in this report was found to have 100,000 bacterial units capable of forming colonies in the machine’s water reservoir.

Meanwhile, coverage at notes that if you leave the coffee grounds in your coffeemaker for 24 hours, you create ideal conditions for some very problematic mold to thrive.

According to Charles Gerba, who teaches microbiology and environmental science at the University of Arizona: “A lot of people leave the coffee grounds in the machine, and they stay moist. Mold has a better chance of growing in there than bacteria.”

To protect yourself against the invisible organisms that can colonize your coffeemaker:

  • Clean every removable part of your coffeemaker with soap and water every time after you’re done making coffee. You may be able to clean some of these parts in the dishwasher – but if they’re made of plastic, wash by hand. The high heat of a dishwasher can break down the chemicals in plastic.
  • Use a fresh paper towel to clean your coffeemaker. Otherwise, your sponge or scrubber may transfer bacteria to the coffeemaker.
  • After you make coffee, immediately dispose of the used coffee grounds or coffee pod. Otherwise they can be a home for mold.
  • Frequently run the coffeemaker through an entire internal cleaning cycle. Check the owner’s manual for how to do this. For pod-use coffee makers see manufacturer info for instructions.
  • Get in the habit of washing your hands before brewing coffee, just as you would before cooking.

You might think because water is heated, that germs would be killed each time you brew coffee. But to do that water needs to reach boiling point and continue to boil for a full minute to kill harmful contaminants.

So to be on the safe side, and maybe even improve the taste of your coffee, be sure to clean your coffee maker regularly.

Carl Lowe

By Carl Lowe

has written about health, fitness and nutrition for a wide range of publications including Prevention Magazine, Self Magazine and Time-Life Books. The author of more than a dozen books, he has been gluten-free since 2007.