Inside my Moka pot water chamber there is build up. It looks black/brown colour, as if coffee has been leaking into the water chamber, and then burning on. Or maybe just coffee oil.

Any tips on how to wash it? I did manage to scrape a little bit and it does seem to expose metal underneath. Any sort of soak would be nice.

dirty moka pot water chamber

  • What have you tried? As daunting as this buildup looks, I've seen roughly similar patina on ill-used coffee mugs, and a wash with water has always impressed me with its surprising efficacy. See this similar Question and my Answer.
    – hardmath
    Dec 26, 2022 at 4:39
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    I have tried descaling by brewing white vinegar solution once. And soaking for like 5 minutes and rubbing. Will try a longer soak & rub.
    – xnox
    Dec 26, 2022 at 14:42
  • Try some baking soda and warm water to soak. The brown goop probably consisted largely of what are called tannic acids, and reacting with a mild base (the sodium bicarbonate) can produce organic salts that are more soluble in water (as a polar solvent).
    – hardmath
    Dec 26, 2022 at 16:31

1 Answer 1


Soaking in vinegar seems to have helped the most.

after vinegar

Now it looks like something baking soda might work on. Or maybe will do vinegar again. Overall I am already happy with the result.

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