Bigsnake
Well-Known Member
You don't need ANY coolers for all grain. You can mash in any vessel but to answer your question, when you see two cooler, one is used as a mash/lauter tun and the other is a HLT (hot liquor tank). This second cooler is only needed if you FLY sparge because you need to keep your hot water up to temp for a good 50-60 minutes.
You can get away with one pot and one cooler though. Read my all grain primer.
+1 for Bobby_M's all-grain primer.
I used a two addition sparge like he recommended, and other than it being really labor intensive, it worked well!