Is Your Coffee Maker Overflowing? Here's Why.

In Consumer Reports' tests, some coffee makers were more likely than others to overflow

Coffeemaker surrounded by puddle of water Illustration: Consumer Reports/iStock

When Consumer Reports began hearing from consumers that their drip coffee makers were overflowing, sometimes spilling hot coffee and grounds onto the counter, we decided to investigate. Were they putting in too much coffee? Too much water? Both?

To get to the bottom of the matter, we added a test to our already challenging battery of brewing performance tests in an effort to duplicate the problem. We filled the filters to within a half-inch of the top, then added the maximum amount of water indicated on the machine. If the owner’s manual specified a maximum amount of coffee, we tried it that way, too.

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The results were decidedly mixed. When an overflow occurred, the appliance spilled hot coffee onto the counter, sent coffee and grounds around the basket, or deposited grounds in the coffee itself. Also, the overflow could happen at almost any point in the brewing cycle and not just at the end, as you might expect from a full carafe.

We flagged the models that were more prone to spillover in our tests, adding a note to the model page. For example, our top-rated coffee maker, the Cuisinart DCC-T20 Touchscreen 14-Cup Programmable Coffee Maker, didn’t overflow. But another Cuisinart with brewing performance rated Excellent, the Cuisinart DCC-3400 12-cup Programmable Thermal, did overflow occasionally.

The one- and two-mug models we tested performed significantly better. The only one that overflowed was the Kitchen Selectives CM-688, which also earned a subpar score for convenience in our lab tests.

Mary Beth Brault, a spokeswoman for Hamilton Beach, which manufactures coffee makers, says the company tries to troubleshoot when it receives complaints about overflowing. Circumstances that may cause the filter basket to overflow or the coffee maker to brew slowly include excessive amounts of ground coffee or a grind that’s too fine. Or the appliance might need cleaning. “Use slightly less grounds when brewing decaffeinated, flavored, or finely ground coffee,” she says. “Or use medium-ground coffee.”

Sometimes it’s the filter that’s the problem, Brault says. If you’re using a paper filter, she advises rinsing the filter basket before inserting the paper filter, then making sure it’s completely open and in the proper position. And check that you haven’t accidentally used two filters instead of one.

If your coffee maker still overflows after taking these precautions, you may have to resort to brewing smaller amounts to avoid filling the filter basket to the rim. “If you want a stronger brew, make a smaller batch of coffee,” says Jim Nanni, associate director of appliance testing at Consumer Reports. “You just might need to brew additional carafes of fresh coffee. But being the coffee lover that you are, that’s probably a good thing.” It’s a trade-off, but it’s better than having grounds in your last gulp of coffee.

Shopping for a coffee maker? When you compare models in our full coffee maker ratings and recommendations, look on the model page in the Highs and Lows section for information on whether the ones you’re considering overflowed in our tests. And check out our coffee maker buying guide for more shopping tips.

Mary H.J. Farrell

Knowing that I wanted to be a journalist from a young age, I decided to spiff up my byline by adding the middle initials "H.J." A veteran of online and print journalism, I've worked at People, MSNBC, Ladies’ Home Journal, Good Housekeeping, and an online Consumer Reports wannabe. But the real thing is so much better. Follow me on Twitter.