How to Spot Insect Infestation in Dried Beans with Pictures

Infested kidney beans with small insect holes in peelA few days ago, I wrote about the reasons that beans may not get hard after cooking. Today I’ll address a different issue that also relates to beans that may have not been stored carefully: infestation. To avoid problems of infestation of grains and legumes, first follow the suggestions in my earlier post on how to prevent insect infestation.

I generally prepare beans in bulk, especially types that take a long time to cook.  The other day, after soaking a kilogram of dried kidney beans, I noticed many suspicious-looking holes. Holes are a sign that insects have invaded and may have taken up residence in your food. I’m pretty sure I would have noticed the holes before soaking, had I looked carefully, but soaking enabled me to take them apart and look inside. I am sharing the pictures with you, of course. If the idea makes you queasy, I suggest you stop reading now.

With light-colored beans, like navy beans, you can actually see the insect residing under the skin if the beans have been soaked.

After soaking I picked up small handfuls, lay the beans out on my palm, looked for blemishes, and flipped them over on to the other hand to view the second side. I didn’t open them up right away, to save time. I found 20 or so infested beans in the package. In the end I only needed to open a few samples to see that most  were not worth salvaging. In  a few cases, the infestation only went a couple of millimeters deep.

Below you can see a bean with one hole, and how it looked inside:

Here is another bean, with two insect holes:

Despite this being the worst case of infestation I’ve seen in a long time, most of the beans were fine and tasty. They did take a long time to cook, though.


  1. Thanks, you said that you soaked 1 kg of beans. Assuming you didn’t use them all at once, how do you keep them? Freezer?

  2. Stephanie says

    But you didn’t say what insect this is, and if they are dangerous. My beans are infested, not all of them and I would like to know if I should throw all of them away. And I would appreciate if you could add the name of this insect. Thanks.