Why Is There White Residue In My Moka Pot? How To Fix It

Found some white residue in your moka pot and wondering what it is, how it got there and how to get rid of it? Here’s what you need to know.

White spots in/on your moka pot can either be aluminum oxide, water spots or mold. Aluminum corrosion is no cause for concern. Water spots and mold can easily be taken care of by boiling all ports of a moka pot in a mixture of vinegar and water. Dry carefully after doing this.

White vinegar will work but if you want something specific and stronger, try this coffee maker cleaner on Amazon.

How you can remove those spots, how they get there and if it has an impact on your coffee will be explained below.

What is white residue in a moka pot?

When you see those white spots, you probably wonder, what is that?

There are three options;

  • Aluminum corrosion
  • Water spots
  • Mold

Aluminum doesn’t rust like iron does. It can corrode in some situations though. This corrosion is also known as aluminum oxide. It often looks like bubbles. Like bad paint with air or liquid under it. Of course if you’ve got a stainless steel moka pot, it won’t be aluminum corrosion. It can still be one of the two next possibilities though.

The next option is water spots. Water has minerals in it. In some places there is much more than in other places. If there are a lot of minerals in the water where you live, this can be a possible cause for your white spots. When the water dries, the minerals don’t evaporate. They are left on the surface which becomes visible as white spots.

The last option is mold. There are many different types of mold. Some types show up as white others as black.

Do white spots affect the coffee quality?

You might be worried if the white spots will impact the quality of your coffee. Does it change the taste or make your coffee unhealthy?

Want to know how to use moka pots to make good coffee step-by-step? click here.

White stains moka pot

Everything that’s on the outside obviously won’t influence the taste of your coffee or leave any residue in your coffee that can influence the taste or cause health effects. But what about the spots on the inside?

Aluminum oxide forms everywhere and very quickly on any exposed aluminum surface. It protects the surface below it from further corrosion. As long as it doesn’t flake, just leave it alone and it’ll be fine.

Water spots are actually pretty hard and won’t come off easily. If that was the case it wouldn’t build up over time. Theoretically, if a bit of mineral deposit lets go and dissolves in your coffee, it could influence the taste but it’s going to be very minimal. Periodically cleaning your moka pot of deposits is still a good idea though. Since the deposits can also get into the safety valve, it could block it which can lead  to a dangerous situation.

Mold should of course be taken care of as soon as possible. Mold can have pretty bad health effects. And even though boiling water will kill most spores, it’s better to give the whole thing a good cleaning.

How to get rid of white spots in a moka pot

Luckily it’s possible to get rid of these white spots and it’s not even that difficult. Here’s what you do.

Aluminum corrosion is OK and as long as it doesn’t flake off, you don’t need to worry about it.

Water spots and mold should be taken care off and luckily you can do it in the same way. The approach you take depends on if the spots are on the inside or the outside.


If the white spots on the inside you just brew a pot of… water.

  • Put water in the boiler of the moka pot
  • Add a tablespoon of vinegar
  • Assemble the pot but don’t use any coffee grounds.
  • Boil the pot
  • When cool enough, dry off all parts carefully

That will spread out the water vinegar mixture through the moka and in every little corner. This should take care of most of these spots. If some residue is still left, rub down the spots with a non-abrasive cloth. Some rubbing will likely take care of the more stubborn white spots.

If there still are some spots, make a 50/50 water vinegar solution. Rub the spots with the same cloth. It can be tempting to use steel wool and that will surely work but it’s also damaging to the aluminum moka pot.


If the white spots are on the outside boiling water on the inside isn’t going to do anything. However, the principle is the same; Water, vinegar and heat.

  • Disassemble the moka pot
  • Put all the parts in a big pot
  • Fill the pot with water
  • Add vinegar
  • Bring to a boil for about five minutes.
  • Get the parts out of the pot and dry them off when cool enough.

Just like with the spots on the inside, if this doesn’t do the trick you can try a stronger vinegar solution or even steel wool

Of course if you have white spots on the inside AND outside, you should use this second method.

How to prevent white spots on a moka pot

To make sure these nasty white spots don’t come back, keep these guidelines in mind.

  • Never put your (aluminum) moka pot in a dishwasher
  • Don’t use detergents for cleaning. Just warm water and something non-abrasive is enough.
  • Dry after washing
  • Store disassembled, dry, and in a place with some little airflow
  • Clean the pot after use

By following these guidelines you’ll largely prevent white spots and residue from forming.

After cleaning

If you’ve deep cleaned your moka pot with vinegar and/or even steel wool, you’ll have to break in your stovetop espresso maker like when it’s new.

What this basically comes down to is brewing a few (3-4) batches of coffee you don’t drink but throw out. This will coat most of the moka pot in a thin film of coffee oils. This prevents a metallic taste from getting into your brew.

Suggested: How to break in a new moka pot.

This also limits the transfer of aluminum which can have detrimental health effects. Although even without proper care this is very limited.

Favorite Moka Pot Products

You don’t need many things to brew good coffee with a Moka pot. Here are the few things you need to make the best possible coffee.

  • Moka Pot: Just buy a high-quality Moka pot from the get-go. The cheaper ones can be messy when brewing. Bialetti is the original and still one of the best with its classic looks. They cost a bit more than the cheap ones but these can last for decades and the parts that wear out are easily available for the Bialetti Moka pots. The 3-cup size is good for a single person (Amazon)
  • Beans: Good coffee starts with good beans. You can’t make bad beans taste good. Espresso roast beans are good for a Moka pot and will get you closer to that typical espresso taste. Peet’s Coffee does a great 100$ Arabica espresso roast. Give it a try, you can get it here on Amazon
  • Grinder: Using whole beans means you need to grind them at home. This improves the taste because the grounds are much fresher. A Hario Slim (Amazon) is a great starting point for the starting home barista. If you want a good hand grinder for a good price, check out the TimeMore C2 (Amazon)
  • Scales: To get consistent results, a set of accurate scales is essential. Check out this Apexstone scale (Amazon). I’ve been using it for more than a year and while it doesn’t look the sleekest, it’s cheap and just as accurate as more expensive coffee scales. It just reacts a little slower.


Welcome to CoffeeImproved! Since falling in love with coffee, I've been on a journey to improve my morning cup day by day. That means I've tried many different brew methods, beans and equipment and experimented with all of them to find what I like. This is where I share what I've learned with you.

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