Coffee Maker Overflowing? Here Are 4 Reasons Why

A coffee maker overflowing is something coffee lovers regularly deal with. Fortunately, the causes are usually simple and easy to fix.

Coffee maker overflowing
Coffee makers overflow because of four possible reasons

If you make your coffee, chances are you have experienced a coffee maker overflow. For me, what happened resembled a localized flood, leaving me scrambling and shocked that so much liquid could fit in that little machine. 

Here you’ll find four reasons related to the basket and the filters you are using. You’ll also find out how to stop it from happening again.

Causes Of Coffee Maker Overflowing

A Dirty Basket

That basket that holds the filter and your ground coffee is a collector of grime if you do not clean it regularly. That grime builds up and eventually obstructs the outflow of the coffee. It can even result in a full-scale blockage.

To avoid this, I run mine in the dishwasher at least once a month. If you have no dishwasher or your basket is not detachable, occasionally wiping it down is a good idea. You should also inspect the basket between washes and make sure coffee grime is not building, as some types of coffee have more fine sediment than others.

A Double Filter

Unbleached vs. bleached coffee filters
Double-check your filter

Almost everyone has used two filters accidentally. If you are lucky, the only issue is that it will take a little longer to get your coffee.

In most cases, though, the water cannot get fast enough through the ground coffee and two filters, so the filter becomes overwhelmed as the basket backs up and overflows. Learn more about coffee filters and water.

The solution is to be more careful. Double-check that you are only putting in one before putting the white or brown filter in the basket.

One way to help avoid the double filter issue is to put any double filters you find aside and only use them at the end. You would still have to inspect each filter before using it, however.

Cheap Coffee Filters

This isn’t a hard sell for buying expensive coffee filters. After all, you can buy a packet of good coffee filters for under twenty dollars. 

However, some less expensive coffee filters (and coffee filter substitutes) are so fibrous they’d probably sprout roots if planted in your backyard. That roughness can obstruct the flow of brewed coffee into your outlet, and that can back the water up to the point it overflows.

Folded Over Filter

Are bleached coffee filters safe?
Use filters that are less tree-like

Less expensive filters also tend to collapse when wet. That can lead to coffee grounds escaping and clogging the outlet. Once the outlet is obstructed, the water backs up until it overflows the basket.

You can only solve these issues by buying filters that are less tree-like and a little more the density needed to allow a free flow of coffee while not collapsing. The good news is there are generic brand coffee filters you can buy that work great.

The Perfect Storm Of Overflowing Coffee

Coffee maker overflows can rarely be attributed to a single reason. Usually, at least two things go wrong. For me, the overflow was caused by all the above.

I had not cleaned my basket in, well, ever. I double-filtered because I was not paying attention. My filters were so cheap you could probably use them as tissues in a pinch, except the giant tree fibers might lead to chafing.

The fact they were so cheap explains why they folded over and allowed coffee grounds to escape, stopping only when held in place by the grime.

The result was more half brewed coffee on my counters, cabinet beneath, and floor than in my coffee pitcher. Fortunately, my neglect aside, everything was easily fixable.


  • Aisling O'Connor

    Aisling is an Irish food and drinks writer and journalist fueled by coffee and herbal tea. She followed up her journalism degree with nutrition studies. Find Aisling on LinkedIn.