You certainly could, but it is unnecessary, as long as you have liquid water in the container.
Good point. Yes, you
can transfer heat to the canister via some of the water you're heating, but there's no
need to unless your flame is weak. As long as you've got a good flame, don't mess with it.
I guess I have always been attracted to hotter items..
I can't say things like that. My wife would slap me.
HJ