Mashing out. Lots of homebrewers don't do it; all homebrewer's should. Why? Many reasons. First of all, raise your hand if you have ever had a stuck sparge? One of the key benefits to mashing out is lowering the viscosity of the liquid inside your mash tun. In other works, thinning it. This is especially important if you are using lots of non-barley grains such as wheat or rye (or pretzels). Also, many brewers tend to mash at a 1 quart per pound of grain ratio. Which, if not hot enough, could stick. Better put, is more likely to stick.