But would it not depend on what your sparge volume was? Is there an approximate mash to sparge water volume? I know it all depends on your SG target/grain bed depth but if you had a nice deep grain bed in, say, a 750L, or 1,000L, tun would it be impractical to mash/sparge 1500L through? I certainly wouldn't want to do multiple mashes to obtain the 1,500L wort to fill the fermenter