I've been AG brewing for about 5 years now and like everybody else I'm always looking for reasons to tinker and upgrade my equipment/processes. Recently I've been looking at upgrading my sparging setup and have been looking at stuff on line. My question is this: It looks like 99% of sparging is done without the mash tun lid on. It would seem to me that you would want to control the sparge water temperature as much as possible, and an open top is counter to that. I'm thinking of an isulated cover of sorts that will allow me to still moniter the water level. Any comments?