From a scientific perspective, kidney beans contain a type of sugar called raffinose, which can be difficult for some people to digest. Draining and rinsing the beans can help reduce the gas-causing effects of this sugar. However, if you're using cooked kidney beans, the raffinose has already been broken down, so draining might not make as big of a difference.
Drain Kidney Beans In Chili at Lori Santiago blog
Now, you might be thinking, what about the environmental impact? It's true, using canned beans can be more eco-friendly than cooking dried beans from scratch. But, if you do choose to cook your own beans, you can always use the leftover liquid as a natural fertilizer for your garden - talk about reducing waste!
