Question: do mung beans have to be soaked?
Answer: Whole mung beans need to be soaked in lightly salted water at least 4 hours and preferably 5. You'll need 2-1/4 cups of soaking water for every cup of beans, and include 1/2 Tablespoon of salt to improve soaking. The dal needs to be soaked for at least a half hour, but if it's old even a couple hours won't help much.