Kidney bean

Kidney beans are a variety of bean with a dark red skin.

They must be boiled for at least ten minutes before they are edible. The boiling degrades a toxic compound - a lectin[?] - found in the bean which would otherwise cause severe gastric upset. Kidney beans are usually canned[?] with water and salt, sometimes also sugar, but the water turns translucent yellow and gloppy by the time a consumer opens the can.