Potatoes soaked overnight do not lose their nutrition value. However, you must ensure that you cover them up completely in water. Or they will turn a horrible brown or grey the next morning, which will cause you to lose your appetite for potatoes. Be sure to refrigerate your soaked potatoes and if possible to change the water at least once. The next morning, you will find that the water is foamy. Empty out the water and rinse the potatoes before using them. Soaking potatoes overnight are helpful if you are rushed for time in the mornings or have to cook for a large number of people.