So your mash tun is responsible for holding your grains and your water at a certain temperature for a proper conversion, where the fermentable sugars are extracted from the grains. If you were to just leave it all in a pot, the temperature would drop too much rendering the conversion useless. There are two methodologies to address this in a Brutus 10 clone. The first would be to add a burner under your mash tun, and then simply heat the vessel when it drops below a certain temperature. The other is to insulate your mash tun. I decided to go with option B and insulate.

I did this for a few reasons. For one, I didn't want to use any more propane than I need to. Additionally, that would require another burner, more gas piping, another igniter, more burner mounts, another wind deflector/heat shield and so on, not to mention the pain the ass of having to have precise temperature control to turn the burner on and off automatically, or even worse, manually. Lastly, heating the bottom of a vessel means unequal heat distribution, which brings up another whole can of worms. Insulation on the other hand, is rather simple, just... add insulation to your vessel.

It seem like half the world heats their mash tun, and the other half insulates theirs, so there is endless information on the interwebs regarding insulation types, and what people have had success with. I chose to go with foam rubber insulation, 3/4" inch thick. It is closed cell so it is basically waterproof, and it is soft and flexible which means it would be easy to attach to my mash tun. It has a heat flow rate (or K factor) of 0.27 Btu/hr. Without getting too scientific on you, this just means that you will lose .27 BTU per hour at 1 inch of thickness. Mine is only 3/4" thick so I will lose slightly more. Needless to say, I think the temperature will only drop a negligible amount over the amount of time my grains are in it.

The foam came in 3 foot by 4 foot sheets, so I picked up three sheets. I then just cut them to the sizes I needed and applied them to the vessel using some real nasty glue. Amraflex contact adhesive looks like snot, and has the properties of snot, so getting it on there was a bit of a challenge. Also, the adhesive is very unforgiving, so you have exactly one chance to get it on there correctly. I did not. My pieces went on crooked, so it was a challenge to make it look 'right'.

Here are some photos of the process and the final result.











It aint the prettiest mash tun in the world, but I have seen far worse. In the long run, I am not sure how well the insulation will stand up to the elements, being handled, and moved around, but worst case scenario, I can just redo it later.

I can practically smell the beer breweing already