Why Does My Moka Pot Keep Sputtering? Causes and Solutions


Why Does My Moka Pot Keep Sputtering header image

Is your moka pot just making sputtering noises and you don’t know what’s going on? Here’s what the possible problems are and how to fix them.

Sputtering is a sign the moka pot is finished brewing. However, if a moka pot sputters before brewing any coffee, it means that not enough pressure is being built, the pressure is lost on the way to the collector or there is too much resistance in the filter and/or coffee bed.

Below you can find the exact reasons why a moka pot is sputtering at the wrong time and how to fix them.


Why Does a Moka Pot Sputter?

There are two moments in the brewing process where a moka pot can sputter. In the beginning of the brewing process or the end. It’s very unlikely to happen in the middle and then resume as normal.

We’ll go into what it means when your pot makes these noised at the beginning and end later. but first let’s quickly go over where the sound is actually coming from.

The sputtering sound you hear is almost always the water in the tower not getting all the way up and into the collector. It’s basically like the gargling you do after brushing your teeth. Too much air, and not enough water or not enough pressure to get the water all the way up.

In some cases there can be sputtering sounds from the threads that connect the boiler and collector. Alternatively the safety valve can be leaking pressure which can also sound similar. You can see if there is pressure/liquid leaking from the threads or safety valve with a quick visual inspection.

If the pot is leaking from the threads, the two parts are probably not screwed together tightly enough. If they are and it’s still leaking, inspect the silicone gasket and make sure it’s in the correct location. There are replacement gaskets available online.

If the safety valve is leaking, a good cleaning is likely going to be enough to make it seal properly again. Boil the parts of the moka pot in a big pot with water and vinegar. This will dissolve any deposits that prevent the valve from sealing. Opening and closing the valve by hand after cleaning will show if it moves properly. In case the cleaning procedure doesn’t help, the O-ring in the valve is probably degraded and can’t seal properly anymore. In that case it’s time to replace the valve. For the popular brands it’s quite easy to find replacements.

Coffee flowing into the collector of a moka pot
Coffee flowing smoothly like it should.

Sputtering At The End

If the sound is not coming from the threads or valve, it’s coming from the tower (the part where the coffee comes out). As said before, this can happen at the beginning of the brewing process or the end.

Let’s first take a look at what’s going on if your moka pot is sputtering in the end. This is nothing to worry about and is completely normal at the end of the brew. It just means your coffee is done. It’s a good indicator it’s time to take the pot off the heat because keeping the pot on the heat can cause the coffee to become very bitter.

If you don’t take the pot off the heat, it can keep sputtering because there is not enough water left to create enough steam/pressure to push the last bits of liquid all the way up the tower. This is fine, there will always be a little bit of water left in the bottom of a moka pot.

Read more about when moka pot coffee is done here.

You can hear some sputtering because there is some water left in the boiler/grounds/tower. However, there isn’t enough water left to create the pressure to push the water all the way into the collector. There will always be a tiny bit of water left in the boiler of a moka pot.

You can open the lid of the moka pot to see what’s going on. When you hear the sputtering starting, you’re just a few seconds away from your coffee being finished. The liquid still coming out will be pretty light in color. After about 10 seconds not much will be coming out of the tower anymore and you’ll just hear a sputtering sound.

That’s when your coffee is done. Take the pot off the heat and serve. Yes, there is a tiny bit of water left in the pot but you’re not going to get it anyways. Don’t put more heat into the coffee than necessary because it could lead to your coffee tasting bitter or burnt.

Suggested: My moka pot doesn’t use all the water, is that normal?

But what if you can hear the sound but there is no coffee in the collector?


Sputtering in the beginning

If your moka pot is sputtering in the beginning, that’s a bit more of a problem. Here we’re talking about a sputtering sound before the brew is finished and there is no/not much coffee is in the collector.

There are several things that could be happening with several different causes;

Problems

The sputtering problems can be divided into two categories; losing pressure along the way or not having enough pressure to begin with. Here are the possible causes;

  • Not enough steam is being created: The most obvious cause is that there is not enough steam and therefore not enough pressure to push the coffee all the way up the tower. This can be because the heat source is not hot enough to produce enough steam. Try turning up the heat.
  • Not enough water in the boiler: If there is not enough water to create the column of water that pushes up to the tower, it will also result in sputtering. A moka pot works best if the boiler (bottom part) is filled with water up to the safety valve.
  • Leaking seal: It’s also possible there is enough water and steam but the pressure gets’ lost on the way to the top. The most likely place is the connection between the boiler and the collector. The screw connection has some possibility to leak. Either the parts are not screwed together tight enough or the silicone gasket is old and leaking. Read more about a leaking moka pot here. Try screwing on the parts tighter and if that doesn’t work, inspect the gasket.
  • Leaking safety valve: Another way to lose pressure along the way is through the safety valve. Over time the safety valve can wear out and let pressure out too easily. However, if the steam escapes through the safety valve, don’t assume it’s just the valve that’s broken. It might be the safety valve actually doing what it’s supposed to do; relieve pressure when it gets too high. One of the next things could be going on letting the pressure rise too high.
  • Coffee bed tamped: If the coffee grounds are tamped down, you create more resistance. If the water can still pass through it you can lose enough pressure to prevent the coffee from moving into the collector.
  • Grind too fine: If the coffee is ground too fine, there are really tiny holes in between the coffee particles. This means you need a lot of pressure to push the water through. A moka pot can only create 1-2 bars of pressure which in some cases is not enough. Only a little bit of liquid will make it through the bed of coffee which might not be enough to get all the way into the collector.
  • Filter clogged: A clogged filter does pretty much the same a coffee bed that’s tamped. The water can’t move through and increases the pressure in the boiler but lowers the pressure in the tower causing a sputtering noise. A filter can get clogged with deposits over time or because the coffee is ground too fine. Carefully cleaning the filter screens and using a slightly coarser grind will fix this.

Solutions

If you’ve found your problem above, here’s what you can do to solve that problem.

  • Start with hot water: This doesn’t directly help solve any problems but you’ll be able to find out if there are any problems a bit faster. Starting with hot water knocks a few minutes off the time to build enough pressure. So if nothing is happening or it’s sputtering, you’ll find out faster.
  • Use the right amount of water: You can measure out your water to get the right ratio but make sure the water level is about 2-4 mm below the safety valve. This is not too much and not too little. If it’s too little, you might not build enough pressure, if you use too much it might shoot out through the safety valve.
  • Wait a little longer: A moka pot will usually start with some sputtering although it shouldn’t last more than a few seconds. However, just waiting a little longer might just let things sort themselves out.
  • Screw the top and bottom on tighter: If the water/coffee/pressure is leaking out through the side, the first thing to try is to screw the parts together harder.
  • Check the gasket: If this doesn’t help, check out the silicone gasket that sits between the filter basket and lid. There are two things that can be wrong with this gasket; A. It’s old and doesn’t seal anymore. In that case, just replace it. B. It’s in the wrong place. It should sit between the filter basket and the filter lid. So NOT above the filter lid. Read more about moka pot assembly here.
  • Clean the safety valve: If the safety valve is stuck open (or closed), the first thing to clean is the pot. Read more about properly cleaning a moka pot in this post (Click).
  • Don’t tamp the grounds: Don’t push the grounds down in the basket. Just pour in the grounds and flatten it without pushing down.
  • Check your grind size: Some moka pot filters are a bit more sensitive to getting clogged. If you use a very fine (espresso) grind and your filter clogs up, try a slightly coarser grind. Read more about moka pot grind size here.
  • Turn up the heat: If waiting doesn’t improve the situation, turning up the heat is the next step. More heat will create more steam and more pressure. However, before doing this you should check if all the other things are OK. Because if you’re just building pressure without a way to relieve it, you might have a bad day. If everything else is fine, turning up the heat will likely solve the sputtering. Here’s everything to know about moka pot stove settings.

Boiling noise

It’s also possible you don’t hear sputtering through the tower, seal or valve but a boiling noise.

The water in the boiler will boil and thus bubble for a bit before building enough pressure to get the water moving. This is perfectly fine and part of the process.

However, if you keep hearing this for minutes and nothing else is happening, it’s possible the flow is blocked. Those reasons are already outlined above but here they are again;

  • Grounds tamped (too hard)
  • Filter clogged

As already mentioned, you shouldn’t tamp the grounds in a moka pot. Just pour the grounds into the basket and flatten it out without pushing down. If the grounds are tamped, two things can happen. The water gets blocked and the pressure keeps building. That pressure should get relieved through the safety valve but on an older pot, you can’t be too sure it’s still in working order. The other option is that the water channels through the coffee bed where it’s the weakest resulting in very weak coffee.

The other reason is that the holes in the filter are clogged. This can happen when the grind is too fine. Use a grind a bit coarser than an espresso grind. So if you bought pre ground espresso coffee and it clogs your moka pot filter, try a slightly coarser grind. If you don’t want to grind your own coffee, look for a medium-fine grind.

If you hear the boiling for a while and no coffee is coming out of the tower, turn off the heat and let it cool down before checking if everything is OK. If you just let the moka pot boil and build pressure, bad things could happen.

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 it’s 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.

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