Grind out a solution
One of the absolute worst feelings in the world is not knowing how to stop your coffee maker from overflowing, making a watery mess of wasted grinds and hot water. Even as you rush to turn off your overflowing coffee maker, hot water continues to pulse through the filter basket, and the puddle of murky crap all over your countertop gets bigger and bigger. And all the while, you come to terms with the knowledge that this morning's cup of coffee is either going to require a total redo, or that you're going to be plunking down some cash at Java Joe's instead.
But what if we told you that it's possible to stop your coffee maker from overflowing, and that much of the work required to keep your coffee maker from spilling everywhere is actually preventative maintenance? In this instance, the devil is truly in the details: anything from a clogged filter, a weak spout, or even the size of your coffee grinds could be a culprit when it comes to figuring out why your coffee maker overflows. As mornings are hard enough on their own, we're here to help make sure that you never have to deal with an overflowing coffee maker ever again.
If you find that your coffee maker overflows more than it used to, the first course of action is to give the entire machine a good cleaning. Even if the likely cause of your coffee catastrophes is inside the actual filter basket, it's never a bad idea to keep the machine pristine. The best way to clean a coffee maker is perhaps one of the simplest, too: empty the entire machine of any coffee grinds, water, and leftover coffee. Then, pour three cups of vinegar and six cups of cold water into the machine, and start the brewing process. Let two more water-only brews go through the machine, or until any lingering vinegar taste is gone.
Afterwards, make sure your brew basket is good and clean. One of the biggest causes for overflowing coffee makers is a dirty brew basket—the outer plastic tray that holds your filter and coffee grinds in place. Give that a thorough scrub, making sure that water can flow through the basket at a good rate. If you have a pause and serve coffee maker, make sure the spring-loaded plug on the bottom of the basket is clear of any debris or residual coffee oils that could impede the flow of coffee out of the filter and into the carafe below.
At this point, if you're coffee maker is still acting up, it's time to look to your filter as the next culprit for your overflowing coffee maker woes. Some filters collapse on themselves during the brew process—especially if you're not buying the right size for your coffee machine. If you find that your filter can't manage to stick to the sides of the walls of your coffee maker, either get a larger size, or pre-rinse your filter after placing it into the machine. More often than not, this will help the paper stick to the sides of the machine (in addition to rinsing out that papery taste you can get in your coffee from time to time). Another way to solve this problem is by getting a reusable coffee filter, which will keep its shape and form every single time. Just remember that these reusable coffee filters need a ton of cleaning and regular rinsing, as they're prone to oil buildup.
If all these measures fail to provide you with a spill-proof pot of coffee, it might be time to look at your coffee grinds as the culprit. Yup, the size of your grind has a huge impact on how well liquid can pass through your machine. What works for an espresso machine is much different than an automatic coffee maker, which is why most grinders have a setting to help you create the right grain size for your machine. If you grind your beans at the grocery store, make sure you're using the right setting for your coffee maker type. If you grind coffee at home (which you really ought to be doing in the first place if you want a better-tasting brew), play with different grind lengths and settings, based on what kind of grinder you're working with. Not only will this help you keep your coffee machine from overflowing, it'll also help you dial in the right kind of coffee extraction for your taste. After all, the longer hot water sits on coffee, the stronger (and more bitter) your cup's going to taste.
And if you're still having trouble getting your coffee maker to stop overflowing, you might need to make fewer cups at a time. Although many coffee makers boast are technically capable of making the maximum amount of liquid as advertised on the water tank, few can do so without hitting some snags in the process. When in doubt, you're better off hovering somewhere in the middle of your machine's capabilities. Or, if you want full control over your entire coffee experience, go all-in with a ceramic coffee dripper that makes a single cup at a time, like a Hario V60, and thank me later.