I rarely use them. When I do, I go for about 8 ounces to 1# tops per batch. You usually use them when you have a higher percentage of wheat, rye, etc (grains without hulls) that may pose problems for sparging. Just add them directly to your mash and maybe add another 1/2 gallon tops of water. They don't absorb a whole lot of water, so when I use them, I usually don't add extra water.