Let's say I have a pound of milled barley malt. Let's say American 2-Row, for the sake of specificity. And let's say I have a gallon of warm/hot water that I mix with the grain and let sit for some longish period of time before straining.
How much liquid will I have left over after straining?
Depends on two factors. The extent of your crush and the residual moisture in the malt. The residual moisture can be found in the malt analysis sheet for the specific lot of grain you have. Not always obtainable from the LHBS, because they don't really care about the stuff on a malt analysis sheet as much as a commercial brewer does.
That said ~10% absorption seems to be the average. So I'd expect to recover, 0.9 gallons.
I always calculate a cup of water per pound of grain. (Sorry metric users.) Makes it easy to figure water loss - just divide the weight of your grain by 8 to get gallons lost.
I always calculate 1 L of water to 1 Kg of grain, and is pretty acurate!
