Last night I picked up a 10-gallon cooler mash tun. It was supposed to come with a 12" false bottom, but the LHBS was out of those. Instead they offered me a 10" false bottom, saying that it would work just as well but that my efficiency might be a little bit lower.
How would a smaller false bottom affect efficiency? I'm trying to picture how the smaller bottom would leave wort in the mash tun, but I'm not getting it.