Dried kidney beans contain a natural lectin that can cause illness when the beans are raw or undercooked. Soaking alone is not enough. Use a full boiling stage in fresh water before continuing to cook them tender or adding them to another dish.
Step by step
Sort and rinse the dried beans
Remove stones, debris and damaged beans. Check that you are working with dried kidney beans, not tinned beans, which are already cooked.
Soak thoroughly
Cover generously with water and soak for at least 5 hours; a refrigerated overnight soak is practical. Use a container with room for the beans to expand and keep them covered by water.
Drain and boil in fresh water
Discard the soaking water and rinse. Cover with fresh water in a roomy pot, bring to a full boil and maintain that boil for at least 30 minutes. Start timing once the water is fully boiling. Keep the beans covered with water, adding boiling water carefully if needed.
Continue cooking until tender
After the required boil, continue cooking as the packet or recipe directs until the centres are tender. Do not taste raw, soaked or partly cooked beans before the proper boiling stage is complete. Only then use them in the next recipe stage.
Why a slow cooker is not the first step
A slow cooker may not reach the temperature needed to control kidney bean lectin. Do not put raw or merely soaked kidney beans straight into it. Use properly boiled and cooked beans, or tinned beans, for a slow-cooked dish. Follow any stricter product instructions and use an authoritative altitude-adjusted method where necessary.
