how many quarts per pound of grain mash?
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. And by making the mash more fluid what you are really doing is making the sugars in the wort more fluid. So, you will extract more of them; mashouts give you better efficiency.