I have an old 6-cup moka pot (bialetti) that I recently replaced the filter and the rubber gasket (bialetti brand), however the extraction time seems a bit long, bubbles to soon(almost immediately) and sputters out- resulting in that bitter over-extracted taste. Strangely, it did work fine just a few times after I replaced the gasket but soon after the sputtering started. Thinking that maybe the rubber gasket was faulty, I replaced it again, but still the same problem. In the past, this moka pot has produced good brews with a nice uniform flow.

Could it be something is off with the safety valve i.e. not sealing enough and allowing pressure to escape?

By the way, I also have a 3-cup moka pot one that I have tested with the same process (pre-heating water, grind level, grind amount, medium heat) and the results are consistently good.

  • There is a reddit thread that deals with a similar problem reddit.com/r/Coffee/comments/3au98b/…. To summarize it: Do not temp the grounds when filling, clean the pot, make sure it's sealed properly and use low heat. On their homepage Bialetti also mentions that high heat can cause problems similar to what you describe. They also say Select burner size to fit bottom of pot. For gas stovetop, make sure the flame is not larger than bottom of pot. The flame should not come around the sides of the pot. Maybe these help?
    – schvaba
    Commented Feb 14, 2017 at 14:00
  • As mentioned above, I use medium heat and the sputtering still occurs. I have also used medium low heat and never high heat. I also never tamp. I've read most of the proposed solutions and moka pot tutorials out there.
    – caveman39
    Commented Feb 20, 2017 at 17:09
  • Then I'd ask your pot dealer for advice or replacement. They probably encountered similar cases in the past.
    – schvaba
    Commented Feb 27, 2017 at 11:27
  • I'm in a similar position, and can't ask my dealer as @schvaba suggests as it's a vintage bialetti (60s I think) bought somewhere in Italy. I'm wondering if the gasket needs to be oiled, but first I'm giving everything a good clean (normally it just gets a rinse to keep it nicely seasoned). Rather than ask a duplicate question I've taken the liberty of editing yours to bump it.
    – Chris H
    Commented Feb 19, 2018 at 21:10
  • @ChrisH I'd rather add comments instead of editing the original question. Somehow, we don't know if this was originally the case at first. Still, yours is very similar to the original case.
    – MTSan
    Commented Feb 19, 2018 at 23:36

10 Answers 10


Folks - please be aware that there are at least two different thicknesses (not talking diameter) for Moka pots. I know that Bialetti makes gaskets in at least 2 different thicknesses. If your Moka pot design needs a thicker one and the replacement is the thinner one, the seal will never be what it needs to be and the flow of coffee will be affected. Hope this helps.


I have the answer!

Like many others, the gasket (O-ring washer thing) on my trusty moka pot was starting to disintegrate after years of stove-top brews. I carefully checked the size I needed and ordered a pack off Amazon. After popping a new gasket in I got the sputtering, mostly steam, small fraction of a brew that so many others describe. Same scenario of misbehavior detailed here and elsewhere. The problem is described everywhere with irritable, coffee-deprived fervor.

Potential culprits included:

  • wrong gasket size
  • bent basket (that holds the grounds)
  • coffee packed in too tight
  • faulty safety valve
  • clogs in filter or funnel
  • heat too high
  • and others I'm forgetting

While it's possible any of those issues can still be a problem, I found the solution to be far simpler: screw the moka pot together more tightly. Literally, when screwing together the top half and bottom half (at the gasket seal), close it more tightly while the gasket is new. I had closed it tightly but brew after brew was getting the same problem but then I tried closing it as tightly as I could and voila!

The thing is, when the gasket is new, the rubber is overly firm from the factory. Even if you think you screwed the moka pot together tightly, the new gasket is not molding to the hairline space between the gasket and moka pot. You gotta screw it together tighter in the beginning while the gasket is still new. As the heat and repeated brews loosen up the rubber the seal will become more forgiving and you wont need to tighten as much. But in the beginning you gotta break in the rubber. Only downside is it can be difficult to take apart.

tl;dr- screw moka pot together more tightly while gasket is new. The rubber is too stiff. Screw it tight and then screw it some more. In time the rubber will be more forgiving.


I recently had this problem. I tried all the published "solutions" but had no success. I replaced the gasket, filter, and even swapped out top and bottom with another Moka Pot I had in storage.

After carefully considering the physics of the whole process, I decided that the problem had to be a leak where the funnel's downtube connects to the coffee holder. The way the Moka Pot works is that heating the water causes the pressure to rise in the space above the water, pushing nearly-boiling water up the downtube and through the coffee. This is supposed to happen smoothly, and sputtering starts to occur only when the water level in the reservoir drops below the bottom of the funnel's downtube.

Early sputtering then had to be something interfering with that smooth increase in pressure. Since I had already replaced the seal gasket, the only culprit remaining was the seal where the downtube attaches to the coffee holder.

I ordered a new funnel and now it works as before.

Problem solved.


I had the same issue with my 12 cups Moka Express. I've done some experiments and observed that the edge of the funnel wasn't properly sealing the pot, even with a good gasket or tightening the upper part the hardest I could. So what I've done was simply wrapping the edge of the funnel with a piece of PTFE tape, so that it could seal between the pot and the funnel. After that, bang: my Moka Pot was working perfectly and stopped sputtering!

  • PTFE tape is a good tip, works for me Commented Jun 9, 2021 at 10:55

It sounds like you know your Moka pot well, and it is true that it is an easy way to get deliciously strong coffee. That being said, it can also be very nuanced in how it works. First, your new gasket should seal perfectly well and as long as there is no sputtering from the screw joint, it is good.

Sputtering means that you are forcing too much steam too quickly through the grounds and into the pot. Try using a high heat to get the coffee flowing, then adjust the heat to keep an even flow into the top chamber. It's possible that with a bad seal, extra pressure was being release from the screw joint and now it is all being directed through the "tower".

Maybe try just keeping it cranked on heat for the whole brew, then low for the whole brew, then mix in between. That's probably the best way to troubleshoot this

Hope this helps!


I've had this problem for years, every time I replace the rubber gasket on my 6-cup Bialetti. But I finally found the answer: in my case, what I had to do was replace the metal funnel.

It's very tempting (or was for me anyhow) to empty the spent grounds after brewing by tapping the funnel against the edge of a sink or trash can. However, this can cause the funnel to deform slightly, creating small gaps between the sides of the funnel and the sides of the pot, which then prevents a good seal and causes the sputtering (even when screwed down tightly). So my advice: get a new funnel, and don't empty the grounds by tapping it against anything.


My wife and I came across a stove top coffee maker while sorting the kitchen cupboards. Don't know the make but its one that has 2 parts and it made of aluminum, water in the bottom,coffee grounds in the bottom as well ,heat up the water and it shoots up into the top half making a good cup of coffee. That's the idea anyway,ours made a mess of the cooker top,coffee splintering out of the top. How do I stop this? Started by checking the spout, found it was a bit rough around the top so took a small file, filed of all the rough bits evened up the hole and flattened the top. After a bit more filing, boiling plain water and still spitting. I decided that it needed a baffle on the top of the spout. So I drilled a small hole in the top of the spout, had a rummage in my shed and found a mushroom shape washer , about 1inch across , with a self tapping screw fixed the washer on top of the spout, fingers crossed but no need it worked perfectly, no t a splitter of any kind,the coffee was deflected down and not out. So what was going to the charity shop is now giving good service and good coffee. I hope that this has been a help to anyone who has problems with their coffee pot. Trust me its worth having a go. Roger,from Sheffield


I put in a new gasket and the old gasket. Works PERFECTLY! Double gasket.


I have a different expresso machine, but sputtering is always leakage around the exit seal.

The steel will be harder to clean than the gasket. So whenever this happens I scrub the cup seal with a pad and make sure no grounds get trapped on the edge before inserting the cup.

This works most of the time. Otherwise the inner gasket must be wipe before use to guarantee it is sputter-free. The stainless steel cup tends to compress any fine grinds and stick, so test it for smoothness with your finger.


I’m a recent convert to a Mokka pot. And have been confused by various blogs on the best way to use it. I have found that sputtering early in the brew process is mostly caused by not packing the coffee into the basket evenly. In my experience it should be filled to the top carefully and leave no gaps anywhere. Half filling the basket means that the coffee won’t brew correctly as it needs the water to be pushed through the coffee and saturate the grounds to get all the flavour out. The no tamping rule is also confusing as I fill it to the max but don’t necessarily tamp it because tamping can over pressurise the boiler and that’s no good to anyone as it can cause leakage at the seal or even worse cause the pressure valve to be released and scald someone next to it. The results I get are a very slow extraction with no sputtering until the very end and at that point I cool the pot with running water to stop the cooking process. I use a 6 cup mokka pot that has never given me trouble and I can fill a mug about a third of the way up then top it up with hot water for a good strong brew. I generally get 3 mugfulls from one pot of coffee. And I grind my own beans in a Hario grinder set to 8 clicks back on the grinder this gives me the optimum grid for my mokka pot and the brews are consistent. Hope this helps. Ps. Having read my own recent comment, I realised that the Questioner was referring to sputtering from the gasket area of his Mokka pot. And not to early sputtering from the brewing spout which I’ve already covered. However I did experience the leakage when I first got my mokka pot and the problem was caused by leaving coffee grounds on the edge of the basket that had spilled onto the threads and prevented achieving a proper seal . I now ensure that the head of the basket and the top of the boiler are completely clean. Also it is not necessary to over tighten the pot as this can deform the rubber gasket and damage it over time. I always screw it home and then add just a little extra, any more than that and it is difficult to undo. My mokka pot is a Cafe de chef bought from Amazon and has given no trouble at all

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