I'm new to cooking with beans, and I accidentally cooked dried kidney beans with my chili without soaking them first. Do I just let them cook for a long period of time, or am I in danger of getting poisoned since they were not soaked beforehand?

  • 1
    I don't know enough to definitively say, but there are plenty of articles about how kidney beans are poisonous and should not be cooked and eaten in their soaking liquid. I'll let someone more qualified put this as an actual answer if it's true.
    – MKHC
    Feb 12, 2019 at 10:01
  • Raw Kidney beans take a long time to cook unless pre-soaked. I'd consider letting the whole mess cool, filtering out what liquid I can, then picking the beans out by hand. Feb 13, 2019 at 0:22
  • @WayfaringStranger : if the cooking wasn't too far along, letting everything sit overnight in the fridge would give the beans a chance to hydrate, too. (but you'll want to cool it quickly, so you don't swap one type of food poisoning for another)
    – Joe
    Feb 14, 2019 at 14:43

2 Answers 2


The issue isn’t so much the soak but the cooking.
You need to boil the beans for 10 minutes to inactivate the toxin in them. Cooking at a lower temperature, such as with a slow cooker will not do this.

The problem here is that I don’t know how well the beans will cook if they’re not yet hydrated. You may need to cook them for a bit then bring it to a hard boil for 10 minutes

  • Is 10 minutes long enough? I thought more like 20-30 minutes is required to bring the toxin down to a safe level. Or is 10 minutes assuming fully hydrated, and perhaps 30 starting with dry beans. Hmmm... Feb 14, 2019 at 14:12
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    Most of the advice I've seen calls for 10 minutes (such as from Cook's Illustrated, but it's possible that the other ingredients in the mix (eg, acids) might affect how well things break down. I'd probably increase the time if this was a thick porridge-like consistency (as you won't have as good heat transfer without the ability for convection) ... but then you risk scorching, too. Baking in the oven might be better if that was the case.
    – Joe
    Feb 14, 2019 at 14:41

Oh my goodness! Kidney beans are not toxic! I do this all the time because I don't plan ahead.

If you add dry beans they will drink up some of the cooking liquid. So you need to add enough extra for them to drink. You will need to cook them longer too. That is fine because the longer you cook them the better they are. I routinely cook red kidney beans overnight. I used to cook them overnight and all the next day and then eat them for dinner. If you do this, smoked pork shank or ham hocks are great with it.

  • Kidney beans are actually toxic when raw. The toxin is called phytohaemagglutinin. It's not deadly, but it can cause stomach upsets, nausea, vomiting, and diarrhoea. However, it is destroyed when the beans are cooked properly. So the idea behind this question is a valid concern.
    – Billy Kerr
    Feb 13, 2019 at 17:44
  • I agree eating dry beans is a bad idea.
    – Willk
    Feb 13, 2019 at 17:57
  • 1
    I think the idea is more that if you soaked/softened them without boiling them, you'd be sorry, as well. But I do appreciate the humor. Feb 13, 2019 at 21:18

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