Adzuki beans, also called aduki or azuki beans, are small, red, dry beans often used in Japanese and Chinese dishes. Their small size lets them cook more quickly than other beans, and they have a reputation for not causing quite as much of a gas problem as other beans. Once cooked, eat the beans plain; mixed with sticky rice to form a Japanese dish called "osekihan;" or ground up with sugar to form red-bean paste.
Sort the dry beans. Throw away any that are moldy, pockmarked, shrunken or otherwise unacceptable. Once you finish sorting, repeat the sorting to try to find anything you missed the first time. As you do this more and more, you’ll get better at spotting bad beans.
Place the dry beans in a strainer. Rinse them off.
Place the adzuki beans in a large pot and pour in enough water to cover them well. The beans will expand while soaking, so add enough water for the beans to have a couple of inches of expansion room.
Place the pot in the refrigerator.
Soak the beans at least overnight, if not for 24 hours. You can also boil the water immediately for a few minutes and then set the beans aside to soak for one to three hours. If you boil the beans for two or three minutes and let them sit overnight, you’ll reduce the amount of sugars that cause gas problems.
Drain the beans, and refill the pot with clean water. Again, use enough to cover the beans well, using three parts water to one part beans.
Boil the water and beans and then lower the heat so that the beans and water simmer.
Test how soft the beans are after 45 minutes by cutting one with a fork against the side of the pot. Hold onto the pot to ensure that the pressure from cutting the bean against the side doesn’t push the pot off the burner.
Turn off the heat when the beans are done, drain off the water and add the beans to whatever dish you’re preparing.