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First of all, I've seen Why does my moka pot sputter?, which covers a very similar issue but has no answers and doesn't ask the specific question I have.

My 6 cup Bialetti is probably from the 1960s, but the modern gasket still fits and I've replaced it before (over 10 years ago, but I don't use it daily). It was blowing steam from the screw joint so I checked and replaced the cracked gasket. With the new one, I get about a teaspoonful of thick coffee before the sputtering (that normally marks the end of the brew) starts from the tower. If I leave it sputtering I eventually get a little less than I should, but enough to drink. I don't normally tamp it, but smooth over the grounds with the back of a teaspoon before wiping the sealing face of the basket with my hand. I use a very small gas ring, with flames smaller than the base (a little smaller to start, reducing once the flow starts).

Assuming there were grounds caught in the seal, once I took the seal out and cleaned it, before assembling wet. It behaved much better, but only that time. I normally only rinse the pot (it's very well seasoned) but I'll give it a good scrub before I next use it. I wonder if the seal doesn't seal very well dry, and whether wiping a thin layer of neutral cooking oil over it would help. Is this a good idea?

Chris H
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3 Answers3

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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".

Hope this helps!

Michael Hartmann
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  • Thanks. You describe pretty much what I do usually in terms of heating -- flames almost to the edge of the base at first, then reduced to minimum once the coffee starts to appear, to keep the flow slow and delay the eruption. With the new seal I have to keep the heat higher or the flow stops. – Chris H Feb 20 '18 at 09:22
  • Yeah I would just try a variety of heating profiles. Maybe try just keeping it cranked for the whole brew, then low for the whole brew, then mix in between. That's probably the best way to troubleshoot this. – Michael Hartmann Feb 20 '18 at 18:00
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Disclaimer: I haven’t handled an old Moka in ages. I assume that the design is identical to modern pots

When you disassembled the upper part, did you just replace the gasket, or did you take out the metal filter?
(Here, replacement kits contain two gaskets and one mesh.)

You should check whether the filter or the „pipe“ is (partially) clogged. Especially if your machine is pretty old and „well-seasoned“ the buildup can throw the pressure balance and lead to unwanted behavior.

After that, it’s probably a question of heating again.

And re. your actual question:
No, don’t “treat” the gasket in and way!

Stephie
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  • I took out the filter as well, but didn't renew it (that might only be about 10 years old; they are replaceable). The pipe and filter aren't clogged, but I wonder if the filter didn't re-seat well because of build-up and left a path for steam to escape. It will get a good clean tonight and a test in the morning. – Chris H Feb 20 '18 at 11:19
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I haven't got to the bottom of why it's misbehaving, but it seems much better if I rinse the seal/filter/screw thread with plenty of water before screwing the parts together quite hard. This normally, but not invariably, means that I get almost a full pot before the sputtering starts, as in the past. This does seem to suggest that it's not sealing properly, at least when dry, but the water also lubricates the screw thread so the seal is under more pressure for the same torque.

Edit Jan 2021: It seems to be behaving much better since getting rather hotter than it should have done one morning last yea. I left it on the stove a little longer than planned (that's what having a child does for you) and when I opened it up after it had cooled it was bone dry in the bottom. Since then the seal has worked better, with no need to wet it first or do it up very tight. I assume the rubber slightly deformed under the heat

Chris H
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