insulating material

[matc]

I'm planning to build an insulated mash tun out of an aluminium pot. It will be used like a cooler mash tun, (mix water and grain, cover, and come back and hour later)

What's the best insulation material to get between spray foam, stryrofoam or mineral wool ? Are they equivalent in terms of effectiveness ?

 

[acidrain]

I would say "D" none of the above.
I would use fiberglass insulation. If you get the white stuff, it doesn't give off itchy dust.
Give it a bunch of wraps, then cover it with some wraps of 6 mil plastic taped at the edges and seams.