This is something that has happened to me twice now:

I like making boxed Japanese curry, so I tried adding some sliced (fresh) shiitake mushrooms, because I like them. Before you actually add the curry blocks, it’s basically just a pot of water, meat, and veggies. Like a bland soup. When I add mushrooms and leave it to boil, it froths and bubbles over. This never happens any other time, with any other ingredients. Just mushrooms.

I tried looking up solutions, but it seems like I’m the only one having this problem. Any ideas?

  • Any way to saute/cook them separately? Commented Jun 11, 2018 at 21:47
  • 1
    Are these fresh mushrooms? Dried?
    – Catija
    Commented Jun 11, 2018 at 22:58
  • They are fresh. And I didn't even think of cooking them separately... That's probably the root of the problem. I'm dumb. (in my defense I've really only been cooking for maybe 2-3 years) Commented Jun 12, 2018 at 1:32
  • 3
    You aren't dumb @Thewitchmaker, I've been cooking for over 30 years and I've never heard of that. The main reason I'd cook them separately would be the flavor you get from sauteing them rather than boiling.
    – GdD
    Commented Jun 12, 2018 at 8:27

1 Answer 1


You cannot avoid the foam, it's going to form but you can keep it from boiling over. A foamy pot boils over because the foam traps steam, acting like a lid sitting right on top of the water. Escaping steam takes heat away from the pot, preventing it causes the water to super heat and boil over. You can prevent it by simply stirring, and floating a wooden spoon on the top (actually works).

However, I would prevent this by reducing heat. You don't need to boil your food, a simmer will work just fine and is more gentle on your ingredients, less heat means even with foam it won't boil over. So turn it down and solve your problem.

As for why the foam forms with mushrooms I don't know. With pasta and rice it's the starches on the surface which come off and expand, but mushrooms aren't starchy. I suspect it's other particles on the outside of the mushrooms, or perhaps the spores under the cap. To reduce foaming you could try rinsing the shrooms, that's usually a no-no but as you're cooking them in water it's no big deal. You could saute them separately if you have the time, you'll get a different flavor which you may prefer, although you wouldn't get it that way in a traditional Japanese curry.

Here's an article about foaming in pasta water which may be worth a read.

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