How to Remove Mold From a Coffee Maker (The Vinegar Soak Method I Actually Use)

To remove mold from a coffee maker, fill the water tank with a 50/50 mix of distilled white vinegar and water, run about half of it through, then let it soak for a couple of hours. Flush the rest, then rinse with a full tank of fresh water. The vinegar kills the mold and descales the machine at the same time.

I use my coffee maker every single day, and a while back I noticed mold starting to build up inside the water tank — especially down in the bottom corners and right around the inlet. That’s normal. These machines sit full of water in a warm, humid spot, so gunk and mold find their way in. Here’s exactly how I clean mine out, and why the soak step matters more than the brewing.

Why Does Mold Grow Inside a Coffee Maker?

Mold grows inside a coffee maker because the machine holds standing water in a warm, dark, humid environment — the perfect breeding ground. Water sits in the reservoir and internal lines for long stretches between uses, and that moisture, combined with leftover coffee oils, gives mold and biofilm everything they need to take hold.

The spots that get hit first are the ones that stay wet and rarely dry out: the bottom corners of the tank and the area right around the water inlet/outlet.

Where Does Mold Hide in a Coffee Maker?

The worst mold buildup happens in the places you can’t easily see or reach. On my machine, the visible mold shows up in the tank corners and around the inlet — but that’s only part of the problem.

Behind the reservoir there’s a second internal tank that actually heats the water. On a unit like mine it holds a good 9 ounces of fluid, plus there’s a whole network of hoses running through the body of the machine. All of that stays wet between brews. That hidden plumbing is exactly why you can’t just wipe the visible tank and call it done — you have to flush cleaner through the entire system.

What Do You Need to Remove Coffee Maker Mold?

You only need one cleaner, and you almost certainly already have it: distilled white vinegar. The acetic acid kills mold and mildew on contact and dissolves the calcium and lime scale that builds up inside at the same time.

If you’d rather not measure vinegar, the little descaling pods work too. You drop one into the reservoir, it dissolves, and it does the same job. Either option is fine — use whatever you have handy.

• Distilled white vinegar — cheap, effective, kills mold and descales in one pass.
• Descaling pods/tablets — convenient if you don’t want to mix vinegar.
• A clean mug or the carafe to catch the runoff.

How Do You Remove Mold From a Coffee Maker?

Here’s the exact method I use. The key is volume and time — you want a lot of solution moving through the machine, and then you want to walk away and let it work.

1. Mix 50/50. Fill the water tank to the top with equal parts distilled white vinegar and fresh water. (Dropping in a descaling pod instead works the same way.)
2. Run about half through. Start brewing and run as many cups through as you can — roughly half the tank. This pulls the solution through the hidden heated tank and all the internal hoses, not just the reservoir.
3. Let it soak. Stop and let the machine sit for a couple of hours. This is the step most people skip, and it’s the one that actually does the work.
4. Run the rest through. After the soak, run the remaining vinegar solution all the way through.
5. Rinse with clean water. Fill the tank with fresh water and run a full tank through to flush out any vinegar taste or residue.

Why Does the Soak Step Matter So Much?

The soak matters because vinegar needs time to penetrate mold colonies, break down biofilm, and dissolve the scale clinging to the heating element and the interior walls. Running brew cycles back-to-back only pushes a little solution through at a time — it never sits long enough on the gunk to break it down.

Remember that hidden heated tank and all those hoses. Letting the solution sit for a couple of hours floods that whole system and gives the acetic acid time to clean the parts you can’t see or reach. Let it sit as long as you can tolerate — the longer, the better.

How Do You Rinse the Vinegar Out?

After the vinegar has done its job, run a full tank of plain fresh water through the machine. I usually do one complete tank, and that’s been enough to clear the vinegar taste on my unit.

If you still catch a faint vinegar smell or taste from the last cup of runoff, just run another tank of clean water through until it’s gone.

How Often Should You Clean a Coffee Maker to Prevent Mold?

Run a vinegar deep clean any time you spot mold, and do a lighter descaling pass roughly once a month for maintenance. Between cleans, the single biggest thing you can do is let the machine dry out — leave the reservoir lid and any removable parts open so moisture doesn’t sit trapped inside.

Staying on top of this genuinely extends the life of the machine. Mine is going on six years old now and still works absolutely perfectly, and consistent cleaning is a big part of why. For a fuller routine covering the exterior, drip trays, and prevention, see our guide on how to clean, prevent, and upgrade your coffee station. If you start seeing tiny flies hanging around the machine instead, that’s a related moisture problem we cover in fruit flies in a coffee maker.

Does This Work for Keurig and Single-Serve Machines?

Yes — the same 50/50 vinegar soak works on single-serve and pod machines, since they have the same standing-water and hidden-line problem. The one difference is the mold that collects around the entry and exit needles that puncture the pods; clear those with a paperclip or the needle tool so debris doesn’t end up in your cup.

If you own a Keurig specifically, follow our model-specific walkthrough on how to remove mold from a Keurig coffee maker. And if your machine is also showing a descale warning, see how to descale a Keurig. Espresso owners can use our Breville descaling guide instead.

For a manufacturer’s take on the general clean-and-descale process, KitchenAid publishes a step-by-step reference that lines up with the vinegar method above.

Frequently Asked Questions

Is it safe to drink coffee from a moldy coffee maker?

No. Mold and biofilm can release spores and off-flavors into your coffee, and that’s a problem for anyone with allergies or a mold sensitivity. Stop using the machine until you’ve run a full vinegar soak and rinse. Once it’s properly cleaned and flushed, it’s safe to brew with again.

Does vinegar actually kill mold in a coffee maker?

Yes. The acetic acid in distilled white vinegar kills mold and mildew on contact and breaks down the biofilm they grow in. It also dissolves the calcium and lime scale inside the machine, so a single 50/50 vinegar soak handles both mold removal and descaling at the same time.

How long should vinegar sit in a coffee maker to kill mold?

Let the vinegar solution soak for at least a couple of hours after running about half of it through. The acid needs that time to penetrate mold colonies and dissolve scale on the heating element and internal lines. Longer is better — let it sit as long as you can before running the rest through.

Can I use descaling pods instead of vinegar?

Yes. Drop a descaling pod into the reservoir, let it dissolve, and run it through the same way you would the vinegar solution. Pods are convenient for routine monthly maintenance. For a machine with an active mold problem, though, a full vinegar soak is more thorough because it floods the entire internal system.

Why does mold keep coming back in my coffee maker?

Mold returns when moisture stays trapped inside between uses. The fix is to let the machine dry out: leave the reservoir lid and removable parts open after brewing so air can circulate. Pair that with a monthly descaling pass, and you’ll keep mold from getting a foothold again.