Certain foods need to be soaked prior to cooking to soften them and shorten cooking times. The food is placed in water and made to stand for up to 12 hours. Soaking times vary according to food. Some types of Rice and Beans are good examples of foods that usually require soaking prior to cooking.
Soaking also refers to a technique with cakes where the bottom layer of a cake or an entire cake is made to absorb a sugar solution, liqueur or fruit juice.