Moka Pot Exploding Featured

Can Your Moka Pot Explode? Let the Flavor Burst (And Not the Pot) With These Tips

No one ever expects their usual morning cup of coffee to turn into a messy disaster area… the thing is, it has happened to some Moka pot owners!

But before you think about tossing your Moka Pot out, let me share:

  • the primary reasons why this can happen and most importantly,
  • what you can do to prevent it.

How Does a Moka Pot Work?

A Moka pot is a stovetop coffee maker that allows you to make espresso-like coffee without buying an actual espresso machine.

First known as the Moka Express, it was invented in Italy by Alfonso Bialetti in the 1930s and revolutionized coffee brewing.

The device uses steam pressure to push water through the coffee grounds to produce a delectable cup of joe.

How Does A Moka Pot Work

Unlike espresso machines, Moka pots push water upwards.

  1. Boiling water in the bottom chamber gains enough pressure to move upwards
  2. The water then pushes through the middle chamber where the coffee filter basket rests
  3. Brewed coffee starts filling the top chamber.

The pressurized chamber is the part that can cause problems.

So, Can A Moka Pot Explode?

Yes, a Moka pot can explode, but only under specific circumstances. It never just explodes randomly, though, which is an important thing to remember.

When you heat the water in the bottom container, the boiling water creates steam. As the steam takes up more space in the chamber, the pressure will naturally rise. This pressure needs to go somewhere. So as the water continues to boil, the expanding pressure pushes the water up through the coffee grounds into the top chamber, where the pressure finally escapes.

Moka Pot Pressure Valve Cutout

Suppose that process is ever interrupted and the pressure gets too high in the bottom chamber. In that case, the spring-loaded pressure safety valve opens mechanically to release that extra pressure from the bottom chamber.

This valve is essentially a safety mechanism that acts as a secondary release point for pressure to escape in case there are any obstructions in the coffee brewing funnel.

What Can Cause It To Blow?

If the pressure keeps building and the safety valve doesn’t open, you could have an explosive problem.

This can be because of:

  • There is an obstruction in the safety valveHard water which is high in calcium and magnesium has mineral deposits (or limescale) that can block the release valve. Fortunately, they are very easy to clean.
  • You have a bad quality valve – This is simply one of the main disadvantages of buying Moka pots that are too cheap. They will be made from materials that are not of good quality.
  • Using the wrong coffee grind size – Finer coffee grounds could block the holes in the filter to the point that the water can’t get through anymore.
  • Tamping too hard – This is more common if you used a finer grind than usual as well. You don’t want the grounds to pack too tightly together that they block the steam from going through.
  • Worn rubber gasket – Theoretically if the rubber gasket at the connection of the top and bottom chambers is worn to a degree that coffee/water exits at screwing connection of the chambers, the water pressure could cause the screw threading to fail and the moka pot to burst. But there are obvious signs of worn gaskets, and anyhow, they should be replaced every 6-12 months.

So for the most part, for a Moka pot to explode, there must be an obstruction in the way the device releases pressure.

Dirty Moka Pot

How Common Is It?

Let’s just get this out of the way too: if you’ve been using a Moka pot for years, it doesn’t mean it’s going to blow up soon. And if there is one, it’s not going to be an all-out boom that shoots shrapnel everywhere.

Aside from a more serious separation between the three main parts of the Moka pot, it’s more common for coffee or water to just burst out from the weakened connection of the middle and bottom chambers.

Of course, this is not to say that it won’t be destructive. You’ll mostly likely:

  • Have coffee all over your kitchen
  • Smaller parts of the pot may fly off and hit fragile items like plates or glass.

Then again, there are possibly millions of Moka pots being used around the world at this moment. Most people use theirs without any problem, and an exploding coffee maker is rarely heard of.

I personally have never heard of one from friends or colleagues, but here are 2 I found that have been “documented” online:

And this video:

Are There Signs To Look Out For?

Many of those who had their coffee maker explode have not observed any obvious signs, but this is probably due to the fact that they didn’t maintain their Moka pot as they should have.

  • One I can point out, however, is if you notice that the coffee flows up the top chamber significantly slower than usual. It could mean that the ground coffee is blocking much of the water from flowing smoothly.
  • Another possible sign is leaking between the top and bottom chambers of your pot. This could either mean that both chambers we’re not locked tightly together or the water in the top part cannot escape through the right channels. (Or that the main rubber gasket is worn.)
  • The pressure safety valve also has a small rubber gasket, and if it is old, there may be water leakage coming from the valve itself. If you notice this, get a new valve.

What to do if my Moka Pot is about to explode?

If you see these signs while brewing with your Moka Pot and you’re afraid it might explode, you should turn off the heat from your stovetop immediately.

It’s best to assume that it will explode anytime, so you should leave the kitchen and let the pot sit for 20-30 minutes. Once it has cooled down, you can then take it apart and find out what causes the problem.

How Do I Prevent a Moka Pot Explosion?

Now that you know how your pot could explode, remember these safety tips to prevent this from happening.

Rinsing Moka Pot Water Sink

Clean and descale your pot regularly

Clean your Moka pot thoroughly after every use and descale the bottom water chamber at least once a month. This is simply the best way to prevent any unnatural build-up of gunk and minerals. Check out my complete guide to cleaning a moka pot here.

Moka Pot Pressure Valve Cutout

Keep a close eye on the pressure valve

Depending on your Moka pot’s model, you can press on the valve to see if it’s working. If it moves, that means the spring and the ball inside can freely move under pressure.

Otherwise, you can remove the valve by pushing on it from the inside with a pin. DO NOT press it from the outside as this could get your valve stuck.

Don’t overfill your Moka pot with water

Only fill the bottom container just below the safety valve, the water should never reach the valve. Filling it to the brim eliminates the purpose of the valve as the water itself becomes the reason for clogging.

Get the right dosage

In the same vein, don’t overfill the filter basket with your grinds either. Stick to the recommended amount you can add based on the size of your pot.

Tamp gently

You only want to tamp the coffee container to even out the surface. You don’t even have to make sure the grounds are all leveled. Tamping hard means some grounds could shoot through the filter and cover the holes completely.

Don’t grind too fine

When you use too finely ground coffee in a Moka pot, and God forbid, tamp it hard, the pressure may not be enough to get through the coffee grounds.

The proper grind size for the Moka pot is medium fine. Do not use espresso or extra fine coffee. Pre-ground store-bought coffee is OK as well.

Moka Pot Grind size

You will most likely never encounter any Moka pot explosions personally, I know I haven’t.

But now you know how to keep them from happening.

But if you’ve heard of any stovetop coffee makers exploding for whatever reason, please let me know in a comment below.

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  1. My month-old, inexpensive stovetop espresso maker just exploded making quite a mess! I was fortunately not in the kitchen at the moment…I believe I will try to return this and buy a higher quality one next!

  2. My mother’s moka pot exploded a few days ago. Probably a mineral build-up issue, as our water is very hard. There’s coffee on the ceiling now…

  3. We had a Moka pot explode a week ago. We were using an induction stove (very new for us) at an Air B&B in Croatia. The pot was designed to work on an induction stove (so I’m assuming it was stainless steel). We’d already made one round and my husband was trying to make another. Two thoughts: we were using a very fine espresso grind and he may have ramped it down (not sure about this). It was loud and scary and a complete mess. Took us two hours to clean up the coffee grinds. Luckily our host was cool about it but I’m sure she needed to repaint. No one was hurt but it was a near miss as my husband had his hand on it moments before it exploded.

    1. Wow that sounds bad, but luckily nobody was hurt. Yes, maybe the grinds were too fine, too tamped, but the pressure release valve should have prevented the accident. Unless it was overfilled or stuck.

  4. well, mine exploded just now. Thankfully no one’s in the kitchen cause it is everywhere. They say 6-9 cups but really thats 6 short blacks at the most, its 2 cups with added milk at my house. Still, I would not have wanted to wear that, definite hospital job. It was 3 years old, every day use.
    I suspect a combination of pre ground coffee (I cant find unground beans that are decaf, please dont hate on me for this as I have ADHD and the mix of dexamphetamines and caffeine being on physical anxiety that is extremely unpleasant so ive had to switch cause I still love my coffee!) and maybe too much coffee? anyway, now im Moka less…

    1. Oh my, you’re the 2nd comment this week with an exploding moka pot. Thankfully nobody was hurt, but it’s probably a mess.

      If you’ve been using it for 3 years you had a hang of how to use it and how much coffee to put into it.

      One thing comes to mind, did you ever descale it? If it was 3 years old without descaling, limescale might have plugged up the pressure release valve or made it stick.

  5. Today a 66 year old woman died because of a moms coffe machine explosion. The newspaper reports 90 percentage of burns all over her body. This is puzzling , I find is still hard to believe but you can check Italian newspapers yourself

    Ms Baldoni

    1. I just read about this here. I’m not sure how she could get 90% of her body burned, there is not enough water in a moka pot for that. The articles say she was alone, so she would probably have been using a small 2 cup moka pot, which takes about 90-100ml of water, so it’s hard to understand what happened. She was using a gas stove, so it was probably something with the stove and the gas that caused this tragedy.

  6. Our pot exploded twenty years ago. Luckily nobody was in the kitchen area at the time. The two halves separated where they are threaded together and made a hell of a bang. The white walls were covered on all sides of the large room with coffee grounds, all exactly an equal distance apart of about 5mm between each grain!

  7. I had an explosion a few days ago but I am a novice at this. I now realize it was human error. I over filled bottom chamber. I forgot the top of the coffee filter and finally when I opened the lid to check if coffee was brewing it exploded all over me the kitchen and even hit nearby living room wall. Luckily I was wearing glasses and was not badly burned. The coffee was taking way too long to brew. That should have been an indicator of a flow problem. Lesson learned. Ty for valuable info. Very helpful

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