I found a recipe in the local newspaper to make refried beans. It said to soak them for 36 to 48 hours, draining and using fresh hot water several times. After the time frame, the beans were so slimy and nasty smelling, I just threw them away. The slime was so thick that I could hardly get them rinsed. What did I do wrong, or is this way they are supposed to be? If so it was disgusting. This was my first time, so I need all the help I can get. Thanks for any help you can give.

  • 6
    I hesitate to ask, but just to narrow the possibilities down, you did use dry beans, right? Not canned? Oct 3, 2012 at 12:36
  • did you start with dried beans, or canned? Oct 3, 2012 at 12:36
  • 1
    They are supposed to be slimy, yes. They shouldn't stink, but are you sure you didn't just catch the slight non-cooked beans smell (which doesn't smell too foodlike, to me it is neutral) and perceived it as nasty in conjunction with the slime? If it was really rotten, you did right to throw them out, but this shouldn't happen normally.
    – rumtscho
    Oct 3, 2012 at 14:07
  • Note that direct sunlight during soaking will also hasten spoilage by a good factor. I have also never had to soak anything for more than 12 hours at most.
    – Carmi
    Oct 4, 2012 at 20:07

3 Answers 3


Soaking beans is a normal practice. While 36 to 48 hours is unusually long, they normally shouldn't spoil in this time.

Assuming that your beans did indeed spoil, there are different explanations possible.

  • you misunderstood the recipe and used canned beans instead of dry beans. You can use canned beans for refried beans, but then you have to leave out the soaking and cooking steps.
  • you added something to the beans which bacteria could feed on, for example sugar. While a recipe which recommends this would be an incredibly dumb recipe, there are all kinds of recipes out there, and maybe your paper just printed a bad recipe without testing it.
  • you somehow created favorable conditions for bacterial growth. I am not sure if this can happen, but maybe leaving beans out for that long can lead to spoilage if other factors come into play, for example a very hot kitchen.

If the beans were really spoiled, but you didn't do any of the things above, it is very probable that it was a fluke. Try again, and you can reduce the soaking time. 12 to 24 hours is normal for beans.

It is also possible that your beans weren't spoiled. When beans are soaked, they can produce both slime and froth. This is a perfectly normal chemical reaction caused by complex molecules found in the beans, and it is not a sign of spoilage. A really strong stink will indeed mean that they were spoiled. But if you are not accustomed to soaking beans, maybe you assumed that something is wrong when you saw the slime, sniffed the beans and noticed their normal smell. It is faint, and to my nose it isn't offensive, but it is different from the smell of cooked beans, so maybe you associated it with "not normal" and therefore classified it as "nasty". I can't tell if that happened or not as I can't smell your beans, but if it happened, don't worry. There are lots of things in the kitchen which seem strange the first time. As for throwing out rotten-smelling food, I'd say better safe than sorry.

  • They can definitely start to ferment if it's hot enough and they're left ~ 12 - 24 hours. Usually you see a foam and a strange smell. Doesn't get slimy and nasty though.
    – lemontwist
    Oct 3, 2012 at 15:10
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    ...and the OP said the recipe called for hot water to be used for the soaking. Oct 4, 2012 at 13:05

Soaking in hot water would definitely speed the growth of bacteria. On top of that 40+ hours is an abnormally long soak. Beans soaked that long in hot water could definitely spoil.

I soak mine under refrigeration. It's become habit from some places I've worked. Maybe try again soaking just overnight in cold water.


As others have asked, you did use dried beans, right? If you use canned beans, no soaking is required. Just drain and rinse.

But soaking dried beans in hot water is very strange, and 36-48 hours is an excessively long time to soak them. I wonder if the hot water and prolonged soaking led to spoilage. Soaking in cold water overnight is sufficient. Then drain, rinse, and cook according to the recipe.

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