Eric, you mentioned just static (pumpless) mashing in those stainless kettles. I've always been little unsettled by un insulated mash tuns that weren't somehow heated (ie rims, herms). Could you elaborate a bit more on your experience? You say 2-3 degrees. Over an hour? What were you approx ambient temps?
Prior to adding pump recirculation I was losing 2-3 degrees in an hour with a sleeping bag on top of the mash tun with ambient temps around 40 to 50 f. The mash tun thermometer wouldn't change much, but the wort below the false bottom would cool off, so when I did a manual recirc I would lose more heat. I would fire up the mash tun and manually recirc and found that the temp wouldn't change much, then all of a sudden it would go up 8 degrees. It is easy to over compensate!
I added the pump late this fall and needed to heat and recirc to make up for the winter temps of 20 f. The heat exchanger was just added and made it much easier to control the temps, with an inline thermometer on the out side of the heat exchanger. I used a cooler mash tun for years and it worked fine, but was hard to change the mash temp after mashing in. Stainless mash tuns are tricky in cold weather (below freezing) w/o herms. I suppose I could brew in the basement with fans and window open, but then my house would smell like beer and the wife would not approve.
Cheers!
