And don't say that its main purpose is to hold water. I've seen people say that it keeps meat moist but I don't know that I believe that is the main purpose. Seems like quite a while ago I saw that it helps to moderate the temperature and I think I know how a pan of water can do that but first I'd like to know, is that's its main purpose? If it is then I don't see how a pan of sand or a clay pot saucer can do the same thing. When water boils it takes a great amount of heat to convert liquid water to gaseous water (steam) thus keeping the temperature down once it exceeds 212* F it's absorbing lots of heat energy and keeping the temperature down.