I recently made a stew, not for the first time either, and I've tossed in a few potatoes, cut into cubes. It took about an hour and a half until they were soft. The stew was simmering the whole time.

In contrast, if I put potatoes into water and parboil them, even if I add salt to the water (or things like peppercorns or some herbs), they will be soft in about 15 to 30 minutes.

Why does that happen?

  • I almost ended up posting this on the Chemistry site instead... :-)
    – Ink blot
    Commented May 2, 2020 at 21:23
  • I am thinking that when you boil a potato you don't simmer it. So you are pumping more heat into the liquid at a boil than at a simmer. Or perhaps I am thinking incorrectly... Commented May 2, 2020 at 21:30
  • 3
    Was there something acidic in the stew? (like tomato?) That will slow down how fast they'll soften
    – Joe
    Commented May 2, 2020 at 22:39
  • My experience is the opposite: unless the aim is a potato soup where the potatoes are supposed to completely disintegrate, cubes of about 1 cm are cooked within 10 - 15 min, like e.g. carrot cubes. Vs. 30+ min for potatoes cooked whole (unpeeled, Pellkartoffeln). Though my experience is more with potatoes that are cooked together with vegetables (carrots + peas) rather than with stew. Commented May 2, 2020 at 22:44
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    @Joe I would say this is an answer. Even if this hadn't been the case for the OP, it may very well be for the next person who comes across this question, so I find it perfectly OK to write down one common reason as an answer even without asking if this can have happened here. And I'll upvote if you write it up :)
    – rumtscho
    Commented May 3, 2020 at 10:32

1 Answer 1


This won't apply to all stews, but if there's something acidic in the liquid (such as tomatoes or vinegar), some items will not soften or break down as quickly.

I know this includes both potatoes, onions, pasta and rice, but I would assume that other starchy vegetables would have similar behavior.

But there can be other factors in play, too. Many people cook potatoes to mash in a fair quantity of boiling liquid, while many stews are simmered. As stews often have liquids other than water, we avoid taking them to a full boil for a few reasons:

  • they make circulate inefficiently, leading to scorching on the bottom of the pot.
  • if the liquid is viscous, it will create bubbles that pop and make a mess
  • it cooks off aromatic compounds ... and anything you smell while cooking is something that's no longer in the finished dish.
  • The argument about a mess is not a good one. The majority of cooking is done with a cover anyway, so at worst, you'll have to work a bit harder rinsing the pot and the lid. The other two are good reasons.
    – Ink blot
    Commented May 7, 2020 at 10:30
  • @Inkblot : if it's a tight fitting heavy lid, you can increase the pressure slightly, so when you lift off the lid the pressure drops slightly causing bubbles to suddenly form. (this is not the same as the problem with putting a lid on while frying ... that's moisture forming on the lid getting disturbed when you lift it, and falling back into the oil which is much more dangerous, but they're both annoying)
    – Joe
    Commented May 7, 2020 at 16:52
  • Hm. Fair point, but until someone is buying me a Le Creuset, all my lids have small holes for equalising pressures. :-)
    – Ink blot
    Commented May 7, 2020 at 18:02

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