For many people, the discomfort avoided by discarding the soak water is more important than the small amount of nutritional benefits from using it. If you consistently have problems cooking beans to the desired tenderness within the specified cooking times, it is possible you have hard water. Another sign of hard water is the appearance of a thick white or gray residue on the inside of your teakettle every time you boil water. This is caused by the presence of excessive amounts of certain minerals. High concentrations of these minerals interfere with chemical and physical changes that are supposed to occur in beans during soaking and cooking.
Some cooks suggest adding a small amount of baking soda to the cooking water to soften it.
We don t recommend this because baking soda may give the beans a soapy flavor and its ability to improve the bean cooking process has not been proved. Thiamine is a valuable nutrient and one reason why beans have a reputation for being nutritious. If you have hard water and are in doubt as to whether or not to use baking soda, buy purified bottled drinking water not distilled water for soaking and cooking beans. Bean Arithmetic A pound of beans measures about 2 cups. Beans triple in volume when soaked and cooked.