Converted Keg for Mashtun Insulation Question

[cam0083]

So I’m going to be using a converted sanky keg for a Mashtun tomorrow night for the first time. It’s cold here in MN so I strapped some foam camping pads I had laying around for some insulation and covered the top with a blanket to retain heat. I did a test run tonight with just hot water, here are the results.

Mashtun Test Run:
About 5 gallons of water, roughly 37* in the garage where I did it.

60min: 160*
40min: 156-157*
20min: 154*
0min: 150-1*

I know that it will retain more heat with the grain in there, especially if it has a lot, but the question is will this be enough for insulation or should I be adding something else? I’m planning on using 27lbs of grain with a 154* mash.

[nighthawk]

Do you have a pump that you can recirculate the wort while adding a little bit of flame ?

[johnplctech]

Pre-heat your tun with some water hotter than you want for your strike water and let the temperature stabilize a few minutes then add your grain.

John

[cramer]

I have essentially the same setup and I’m up in MI so pretty cold here too. I use a closed cell foam sleeping pad for insulation and a 1" thick hard insulation piece for the top. Even in winter I only lose a degree or two during a one hour mash. I make about 12 gallons though and most of my beers are bigger so there is more thermal mass in my mash with all that grain and water so I’m sure that helps.