Last Updated on August 18, 2023 by Barry Gray
I love my Moka pot. I’m sure I’ve told you this before, but it’s something I’m not ashamed of.
I feel it delivers some fantastic coffee, even though I admit it took some time for me to master the art of producing quality coffee over and over again. And yet, there are still times when something goes wrong, and it quickly becomes highly annoying.
Take when your Moka pot starts leaking as a perfect example. It’s almost soul destroying when that happens, so what can you do to stop it?
Your Moka pot could leak due to several reasons. You may be using an incorrect grind size, adding too much coffee to the filter basket, tamping the coffee, adding too much water, or failing to clean your Moka pot correctly.
Basically, fixing this problem, and even preventing it in the first place, is not difficult. Still, I will take you through each potential reason and why it causes problems.
By the end, you should be in a position where a leaking Moka pot is a thing of the past. Well, as much as it possibly can be.
Why Does the Wrong Coffee Grind Make Your Moka Pot Leak?
When I started out on my coffee journey, I had no idea you needed different grinds depending on the brewing method. To me, it was all the same thing, and you just used different equipment.
Well, I was completely wrong on that score.
Take your Moka pot as the perfect example. Using the wrong grind size will not only result in your Moka pot leaking, but it will also completely change your finished coffee.
It’s actually very easy to ruin your coffee simply because you haven’t got the grind to the correct size. It can result in the water passing through the coffee too quickly or too slowly, and neither approach will lead to a delicious brew at the end.
Look at the grind you use for both an Espresso machine and a Moka pot. An Espresso machine requires a very fine grind as it uses significantly more pressure to force the water through the coffee than you get with a Moka pot.
If you try to use the same ultra-fine grind with your Moka pot as you would do with an Espresso machine, disaster will strike.
There’s just not enough pressure in your Moka pot to force the water through the coffee. However, there’s enough pressure for it to have to be moved somewhere, and that’s where you can run into the problem of it leaking.
This happens via the pressure valve on the reservoir of the Moka pot. The pot uses it as an escape route, and the water will come out simply because the force is becoming too great, and it cannot get it through the coffee.
Adding Too Much Coffee to the Filter Basket
Let’s say you have picked up the perfect coffee for a Moka pot, so you have a nice medium grind or made it yourself via using a burr grinder. Now it’s time to add the coffee to the filter basket, but be careful as you could cause a problem if you are too eager when adding the coffee.
But adding too much coffee is a common mistake. I stood watching a friend making coffee in their Moka pot. I had to interject when I saw them trying to cram as much coffee as possible into the basket.
They said it would deliver more coffee and better coffee, so I had to break the news to them that this was not the case. Actually, they would be making their life harder for themselves.
The problem with adding too much coffee to the filter basket is you make the coffee too condensed. In a sense, you end up creating the same problem as the previous point, where the coffee is too fine, making it harder for the water to pass through.
By adding too much coffee, you restrict the ability of the water to pass through and make the brew. Again, the little pressure that does exist in a Moka pot forces the water somewhere, so it comes out of that pressure valve again.
But it can get even worse.
I’ve witnessed a Moka pot leaking from the gasket area as well. It’s like this coffee is spewing out of the Moka pot from everywhere, apart from where you want it to come from.
Having it leak from the gasket is simply because you have added so much coffee and water that the pressure valve is unable to cope. Chances are that water will come out of both areas at the same time, and you simply feel as if your Moka pot is going to explode.
Don’t Tamp the Coffee
This feels like a recurring theme here, but tamping coffee in the filter basket recreates this previous point regarding too little space in the filter basket.
Again, this is an easy mistake for people to make. You see people using a coffee tamper when making Espresso, and people automatically presume you can do it with a Moka pot. After all, you are using ground coffee, so it does make sense.
Apart from the fact it really makes a mess of things for you, and it will lead to your Moka pot throwing water out and not coffee.
When you tamp the coffee, you are condensing it, and it then requires a lot of pressure for the water to be forced through the coffee, delivering the drink at the end.
I’m sure you can already guess what I will say regarding the likely outcome when you fire up the heat and wait expectantly for some coffee to appear.
Instead of coffee, you will get water coming out of your Moka pot via the pressure valve and potentially the gasket as well.
Coffee in a Moka pot requires some space for the water to be pushed through, and tamping coffee may look cool, but it does the complete opposite of this for you.
Too Much Water in the Reservoir
I’m moving away from the coffee aspect for now and focusing on the water reservoir itself. Yes, that section at the bottom where water will spew out when it’s unable to pass through the coffee.
Too much water being added to the reservoir can cause problems, and one of those problems can be your Moka pot leaking.
A Moka pot comes with a fill line, and it’s there for a good reason. Adding too much water means the Moka pot has no space available for the limited pressure that builds during the brewing process.
By adding an excess of water, the Moka pot has to push that extra water somewhere, and it uses either the pressure valve or the screw section as its escape route.
Now, with this error, you will still get some coffee appearing in the upper chamber. Still, pressure and water have been wasted with you overfilling the reservoir, so there’s a good chance the coffee will be weaker than intended.
One thing people don’t tend to realize with a Moka pot is it does need things to be clean for it to work correctly.
People make the mistake of thinking a Moka pot is made of stern stuff and it can cope with a lot of use. Well, that’s true, but only when it’s kept in pristine condition, and that includes cleaning it after every use.
The main issue you face is old coffee grains clogging up your Moka pot. That means the pressure and water cannot work their way through the pot to produce the coffee, so as with every other issue mentioned above, the water has to go somewhere.
But there’s another problem with poor cleaning.
Old coffee will sit around the rim of the basket and the area where the upper and lower chambers of the Moka pot are screwed together. Old coffee stuck on the joint leads to a poor seal, and it’s obvious what will happen when there’s a poor seal.
At that point, coffee will come out of everywhere apart from where you want it to appear.
A Poor Gasket
The final reason why your Moka pot is leaking is one I admit I didn’t think about: an old gasket.
The gasket is that rubber seal that sits where the upper chamber is screwed to the lower chamber. Over time, the rubber will crack and split, leading to the seal just not being as good as it should be.
At that point, you need to replace the gasket, but it’s not a big deal, and at least your Moka pot will be back up and running in no time.
My Recap on Your Leaking Moka Pot
Having a leaking Moka pot need not be the colossal disaster your mind is trying to tell you. I know I panicked the first time it happened, but my Moka pot is still going strong and dishing out some delicious coffee.
So, here’s my recap on the crucial points you need to remember if you suddenly discover your Moka pot is rejecting water via various spaces in the pot.
- Check you are using the correct grind size as too fine will cause problems
- Don’t try to overfill the filter basket or you will stop water getting through the coffee
- Never tamp the coffee. Instead, swipe over with your finger to knock excess off
- Always fill the bottom chamber below the pressure valve
- Clean your Moka pot after every use to prevent clogging
- Replace the gasket if it’s old and tired
Looking after your Moka pot should stop any problems as will taking care over how you make your coffee in the first place. I know it’s tempting to add as much coffee as possible, but it’s really not required to get a decent brew via your Moka pot.
There can be a number of reasons why your Moka pot is leaking, but I’ve walked you through the various reasons to help you to find a potential cure. A Moka pot is a fantastic way of brewing coffee, and seeing that delicious coffee spilling out at the wrong time hits hard.
As long as you take your time with preparing your Moka pot, you should have no issues. But if you want to learn more about how to use a Moka pot or even how it compares to other brewing methods, I suggest checking out different articles that appear here on the website.