After soaking dry beans, I place beans on heat, so they boil for couple of hours, and they cook pretty well. But if I add just one cup of cold water (at room temperature) during boiling, temperature of the mixture would drops for some minutes. But then the cooking time of the beans would increase significantly, and it seems they wouldn't cook well ever.

For most of the beans I experienced this process, but I can't figure out why?

  • It may be worth adding some details on the general cooking method and why you're adding the cold water? I'd guess it's simply taking them off the boil so the temperature doesn't remain high enough to cook them.
    – PeterJ
    Commented May 6, 2015 at 16:55
  • I added more details, I hope that it is clear enough.
    – 2i3r
    Commented May 6, 2015 at 17:26
  • There is no logical reason for me to add cold water, just when water level getting low, it's easier to add cold water (at room temperature) to the mixture in pot in comparison with boiling the water first.
    – 2i3r
    Commented May 6, 2015 at 17:33
  • I've never experienced this myself. I've cooked a lot of beans using a lot of techniques, and I've occasionally had to add water when they would start to dry out. Yes, it can increase cooking time, but the beans should eventually soften. (It is possible to have beans that will never soften even with long cooking, but those were just grown under bad conditions. To my knowledge, you can't turn good beans into hard ones that won't cook just by adding cool water.) Anyhow, what type of beans are you using? Have you tried cooking them for a very long time?
    – Athanasius
    Commented May 7, 2015 at 18:25
  • Also, the obvious question -- why not just start cooking them with more water at the beginning?
    – Athanasius
    Commented May 7, 2015 at 18:26

3 Answers 3


If you want to speed up the cooking time and need to add more water, heat it on stovetop or in microwave till steaming, then add. Cook at lower heat just at or below simmer to keep beans more intact and with a cover on to avoid water loss in the first place. NEVER add salt at the beginning of the cooking process, only once desired doneness has been reached. If they just won't get soft (really hard water), add a tablespoon of baking soda to the cooking water, but then they will get soft really fast so watch carefully.

  • Thanks, nice to know, but it's not my answer, since I'm looking for why, not how.
    – 2i3r
    Commented May 22, 2015 at 6:30
  • 1
    Totally missed the why, not a scientist here just a long time cook who usually does want to know why.
    – Fireflower
    Commented May 23, 2015 at 20:04

Because the "cook time" begins when the temperature is high enough for the pot to "simmer". By adding lower temp water you are dropping the pot temp to under "simmer" in effect "pausing" the cooking time until the pot reaches "simmer" again. Once the pot reaches a high enough temp to simmer again the cook time picks back up again. The pause in the middle adds minutes to the over all time it takes to cook your beans.


We cook beans a lot at home; and I just learned from my mother that we don't add cold water to simmering beans, we also don't add any sauces earlier on during the cooking; or the beans would harden. You can always top up your beans with boiling water, and only add the sauce once they are done.


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