Can a Dirty Coffee Machine Be Bad for Your Health?

A woman in a kitchen using a coffee machine.

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Your coffee machine may give you the caffeine boost you want in the morning. But if you haven’t cleaned it in a while, you’re likely drinking in harmful bacteria with your cup of Joe. That’s why our experts are weighing in on the health risks of dirty coffee makers and offering tips to keep the coffee drinkers you love safe.

What is Growing in Your Coffee Machine?

When you make coffee – whether in a drip coffee maker, espresso machine or another specialty machine – you mix coffee grounds, water and heat, creating a perfect environment for microorganisms like bacteria, yeast and mold to thrive. In fact, some recent studies suggest that up to half of coffee makers contain one or more of these microorganisms, including some strains that cause diseases like E. coli and Salmonella.

Dangers of Dirty Coffee Makers

Though not all the bacteria, yeast and mold in your coffee machine are harmful, some may be – especially for immunocompromised or sensitive people.

If you get coffee from a community coffee maker at work, you may face additional exposure to microbes. A Kimberly-Clark study of more than 5,000 office surfaces revealed that 48% of coffee pots and dispensers were in serious need of disinfecting measures.

Additionally, the handle of the coffee pot may be loaded with bacteria and other germs from all the hands that have touched it throughout the day. These common surfaces must be cleaned often, especially during cold and flu season when bugs are already going around.

And, while not dangerous, dirty coffee machines also produce more bitter-tasting coffee over time from hard water build-up. When left unchecked, this scaling may damage your machine.

So, if your coffee machine can be a breeding ground for bacteria, you may also wonder about your favorite mug. And the bad news: we have the same concerns there. A mostly empty mug that you rinse and reuse is prime real estate for germs and bacteria, especially if you like your coffee with cream and sugar.

How to Clean Your Coffee Maker (and Beloved Mug)

Though the high heat of many coffee makers will kill off some of the organisms that can cause disease, it’s best to be proactive about cleaning your machine regularly. That way, you can keep stubborn bacteria, yeast, and mold at bay before they become problems.

The best way to clean your coffee maker will vary depending on the type of machine you have, but it’s important to clean all the parts that touch your coffee. That includes the water reservoir, filter basket and drip tray. Cleaning with water and vinegar — or a special descaling solution — can help disinfect your machine and prevent it from producing bitter coffee over time.

If you’re considering investing in a new coffee maker, consider a mostly glass and stainless steel model since these materials are easier to clean than plastic.

In the workplace, make sure to wipe down the common surfaces on your coffee equipment regularly and place all mugs in the dishwasher, where higher heat will kill most disease-causing germs.

For your mugs and reusable cups or bottles, be sure to follow these safety tips, which include

cleaning them after every use using hot water and soap (soap is essential to remove the bacteria). And if your cup has a lid with multiple parts, like an open-close mechanism or leak-proof gasket, be sure to remove and scrub each part.

From Your First Cup of Coffee and Beyond

No matter how you start your morning routine, AdventHealth is here to help at every moment of your day. Our team of trained primary care providers is here to answer all your questions to keep your family safe and healthy. Learn more.

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