Mash tun insulation

I currently use 2 layers of the double-bubble-aluminum foil for my mash tun.
When I first constructed it, I would only lose less than 2 degrees F over a one hour period.
2 years later, I lose 4 degrees within 20 minutes.

Does this stuff degrade from high heat. Don't think it was designed for 160F+

I'm asking again - anyone know where to get coozie material by the sheet, or the material styrofoam cups are made of. That would insulate exceptionally well.

Thanks, now go drink some beer.

I used styrofoam sheets (maybe 1" thick) that came as packing material in some IKEA-type furniture we bought. You can't really bend it very well, so I cut it into 1"strips, backed it with some of that air duct insulation (adhesive on 1 side) that they sell at Lowe's/HD, and finished it all of with some duct tape and some velcro closures.

With that, my SS tun will lose 1-2 degrees in an hour. 'course, the nest week I went out and got a cooler

I tried the orange 1" styrofoam 3 years ago. I rememer a lot of "pop" noises when I tried to bend. Just pissed me off, so I went with the bubble wrap.
Thinking now, if I put in back yard in sun, and slowly curve it every day, could I get it to tightly fit around a 16" diameter pot.
Also, what does 160F+ heat do to styrofoam.
I know it doesn't bother the coffee cups, but the material is different - much more pliable & flexible.
I never apply heat to my mash tun (obviously), so flame resistance isn't a problem.

I tried the orange 1" styrofoam 3 years ago. I rememer a lot of "pop" noises when I tried to bend. Just pissed me off, so I went with the bubble wrap.
Thinking now, if I put in back yard in sun, and slowly curve it every day, could I get it to tightly fit around a 16" diameter pot.
Also, what does 160F+ heat do to styrofoam.
I know it doesn't bother the coffee cups, but the material is different - much more pliable & flexible.
I never apply heat to my mash tun (obviously), so flame resistance isn't a problem.

Have you tried a water heater blanket?

I have not, because of fiberglass - but never looked at one either. Will do. My preset impression of fiberglass is saggy, etc., but I'll look next time I am at Lowes.
Thanks for the feedback

I have a stainless MLT that is direct fired. I have not insulated it yet, but if I do, it will be with a water heater blanket. Just make sure you don't let the insulation get too near the flame.

If I do, I plan on leaving the bottom 6 or so inches uninsulated just for this reason. Most of the heat will be at the top of the tun anyway. You can also remove it for heating or cleaning if you need to.

I'd think with any insulating blanket, it's probably a good idea to take it off when you're applying direct heat, and put it back on afterwards.

I think those are good ideas.
If you could have a computer monitored system that would stir, monitor temp and kick on and off, that would be a good system.
You'd either be doing it for a living or be like one of our brewclub members.
If you want to see a totally radical setup, go to:

www.mkob.com

Go to breweries

Jason Hayes - first name.

Serious homebrewer here.

Go drink a beer.


gunga galunga.........gunga gunga gulunga (Caddyshack - guess who)

I used to use the fiberglass water heater blanket, still lost a lot of heat (10 degrees per hour!) Grabbed some duct insulation from Lowe's, wrapped the MLT and cut out a piece and placed it inside just barely over top the wort...seems to lose the most heat there to the headspace. Put some on the hole in the top of the MLT and now I get zero heat loss. :rockin:



Complete with some ghetto duct tape. Hey, I didn't say it was pretty...just that it worked.

Another alternative is engine compartment insulation. This is heavy felt with aluminum on both sides. Many places like Kragen or Napa carry it.

And yes the bubble-pac type insulator will degrade at 160F. You could wrap a layer of the ECI and put the bubble-pac back on.

Good idea about the engine compartment material. Thanks

One other thing I do: I cut a circle that just fits in my mash tun. A lot of the heat is lost going up, so I put that on top of the mash.

I'm sure I burned that thing to death also.

Like I said, when it was new, the temp drop over an hour was almost nil.

I'm off to design something that's not as sensitive to high temps.

Thanks again for the feedback.