Hi i have Bialetti Rainbow moka pot which has silicone in the safety valve. I want to know how can i clean this thing after every use? Can hot water rinsing melt the silicone or moving the piston in circular motion as Bialetti suggest pop the silicone or loosen the spring? How do you guys rinse the boiler or lower part of your moka pots?

Оne more thing. After I bought the moka pot, the first two brewings were good and the coffee came out as a liquid, but after the third brew it started to come out like foam. What could be the reason for that?

The safety valve is designed to work at temperatures exceeding 100°C so you don't need to worry about hot water damaging it. The circular motion technique that Bialetti recommends is for dislodging debris or scale in a malfunctioning valve. In normal use cleaning the valve isn't necessary. It's a good practice to pull the valve stem occasionally to ensure that it isn't stuck.

It would be difficult to damage the valve by hand. I tried to break one open once (I wanted a hollow bolt with those threads to use for routing wires into my moka pot). I couldn't do any damage to it and ultimately just used a drill to hollow it out. Even that took a while.

Over time, like many years, the spring may weaken causing the valve to leak at low pressure. If/when that happens then you just buy a new valve or a whole new pot, whichever is easier/cheaper.

I clean the lower part of my moka pot simply by rinsing it with water and then toweling it dry. The basket and upper part require more attention when cleaning since that's where the coffee is.

Hello:

jpender wrote: ... the spring may weaken causing the valve to leak at low pressure

The first time I used a moka pot I had just turned 18 and landed my first job as an errand boy at a two partner architectural bureau.
Naturally, I was in charge of making coffee twice a day on the electric countertop stove.

I lost count of how many times (20, 30?) I jumped from my desk to the smell of burnt coffee/rubber seal due to my forgetting the pot was on the stove.
Not one time did the safety valve go off.

For a properly working safety valve to actually engage, the coffee grounds and the rubber seal would have to resist far too much pressure, something that (in my experience) does not happen.

At least not in a properly used moka pot.
eg: an overfilled and tamped filter may behave differently.

I purchased my go-to 4 cup Italian moka pot second hand, it came with a valve problem: a previous owner had stripped the thread at the Al base.

I simply re-threaded the hole to hold a short allen headless screw with a wee bit of the high temp anaerobic sealer I had at hand and that was it.
I have been using it that way for more than 15 years without any issues.

Best,

CIV

civ wrote:For a properly working safety valve to actually engage, the coffee grounds and the rubber seal would have to resist far too much pressure, something that (in my experience) does not happen.

I've popped the safety valve on my Bialetti Brikka moka pot a number of times. It's a little shocking the first time that happens. In case you aren't familiar with the Brikka, it's designed to accept a finer grind than is typically used in a standard moka pot. It is quite possible to choke it. By extension, it wouldn't be that hard to choke a regular pot as well, if, for example, you thought that tamped espresso grind was what you were supposed to use. Whether the valve releases or the seal fails is an open question for a particular pot, until it happens.

I measured the Brikka safety valve release pressure (using a bicycle pump and a pressure gauge) and found that it let loose at 3bar. As far as I know it's the same valve as in a Moka Express.

I retired my 25+ year old stainless steel Acero moka pot after the valve spring got old and tired. It would leak at anything slightly north of zero PSI. It had different threading than the Bialetti and I couldn't find an obvious replacement. For a while I used it with a plug in place of the safety valve figuring, as you had, that the risk of explosion was small. But I didn't like those odds for long term use. It has happened to people. And anyway, when I bought a Brikka I stopped using a regular moka pot.

Hello:

jpender wrote: ... popped the safety valve on my Bialetti Brikka moka pot ...
... quite possible to choke it.

Granted, it is a possibility and has to be considered.
Which is why the safety valves are there in the first place.

I forgot to mention that my moka pot use involves, on one hand, filling the reservoir with boiling water and on the other, keeping the heat input in the low/low to mid range setting (electric stove) and shutting off power/letting it coast along as ~30% of the brew chamber is filled.

In my opinion, that makes for a safer and more controlled brew.

Best,

CIV

CIV -- you're a brave man! I wouldn't do it. I assume they put that safety valve in the design (in 1933) because there was some chance of needing it.

After having experienced many undesired leaks around the seal I had the same thought as civ, that the gasket would almost certainly let loose before the valve was necessary. I once decided to test that theory. I replaced the valve with a plug and also blocked the coffee exit. Then I loaded the pot and put it on a little backpacking stove, in the garage. I fired up the stove and started watching. As the first few minutes ticked by my confidence began to erode, eventually replaced with fear, and I shut it off before finding out what would happen.

What about pressing the small piston in the safety valve too hard or too often, can that cause spring to loose or the silicone to pop?

Kristijan wrote:What about pressing the small piston in the safety valve too hard or too often, can that cause spring to loose or the silicone to pop?

Sure, there are physical limits to any mechanical device.

I think the valve is fairly robust but there's no reason to treat it roughly. Leave it alone unless you're testing it. If you towel off the interior be gentle around it.