soaked beans in a ceramic bowl - both the bowl and the beans turned blue-ish

Asked March 17, 2019, 11:14 PM EDT

I soaked some dried beans in a ceramic bowl for about 8 hours. Both the beans and the bowl turned blueish. Are the beans now safe to eat? Or are they contaminated with glaze leached from the bowl? Is the bowl safe to use? I have had that bowl for 20 + years. I have attached: 1) Picture of the package that the dried beans were from with more from the same batch still there. They were purchased recently. 2) Picture of the outside of the bowl. Until recently, the inside looked about the same. 3) Picture of the inside of the bowl with blue-ish stain spots. I would include a picture of the soaked beans with blue-ish spots, but I only seem to be able to attach 3 photos.

Oakland County Michigan

3 Responses

Hello,
The bowl is not leaching. Beans are the seeds of fruit (the pods). Both the fruit and the seeds can be colorful, and those colors are from chemical compounds like polyphenols and tannins. When soaked, the colors can leach out. Sometimes the pH of the water can affect leaching, and also the color. For example, some people add a tablespoon of baking soda per quart of water to speed up the softening process, and the interaction between the alkaline soda and the tannins can also augment the color. This sometimes makes new colors, like using litmus paper.

So, there could be a few things at play: bean variety, natural pH of the water, and any additives to the water (salt, soda, etc) that you may have used. It looks to me like maybe one bean type in the bunch is responsible for the blue color. You could try separating them out and soaking each type individually as an experiment and see.

But, no matter the pH, to reduce color leaching, and to maintain truer colors in the final product, use just enough water to cover the beans, adding hot water as needed. Or, use a crock pot and don't drain and refresh the water before cooking.

Thank you! So, if it happens again, they are still safe to eat? I did use baking soda in the soaking water, which I had not done in the past. So maybe that did it. Plus I had a package w a combination of beans, so I guess that was another factor. Much obliged