Mash tun losing heat

[Alsace]

I mash in a 7 gal. round rubbermaid, which has worked really well for about 40 batches. I remember when I got it set up originally I was finding it would hold the mash temp within a degree over an hour. In the last few batches I have been seeing really low numbers by the end of the hour. I try to make sure the temperature is stable before I seal it up, but I seem to be losing 4 or 5 degrees over the course of an hour. So I was wondering, do these things lose their insulating capacity over time and wear?

Is anyone else having problems like this? If so what are you doing about it?

 

[jhalloran]

I have a 10 gallon igloo round cooler and noticed a lot of heat loss. I initially wrapped the mash tun in a sleeping bag to keep the temperature stable, but I read somewhere that the lids are pretty much hollow so I drilled holes in the top and filled it with foam insulation. My first mash with the insulated top resulted in negligible heat loss over 75 minutes.

 

[BrewinHooligan]

I have experienced this recently myself, but I am mashing in a rectangular cooler that has a hollow lid that domes up about 4 inches which is where my problem lies I beleive. I have started placing aluminum foil over the top of the mash and that helps quite a bit, but I will be building something identical to jhalloran's tun very soon.

 

[Alsace]

Thanks for the idea with the spray foam insulation. How many holes did you drill? And did you have to seal off the holes to prevent them from contacting water or are they ok with that?

 

[25518]

Maybe don't go all the way through the lid with the drill bit. Probably depends on the size of drill bit. And how many holes your willing to hammer into it. I wouldn't go overbored, swisscheesing it. Hammer in a hole. Go from the there. That spray foam will go far. Comes in a red can. Forgot the name of it. Home depot, Wallmart, Ace, Hell. I'm sure Target may sell it too. Do one hole. That stuff will squirt out the other holes. Plus the hole you drilled. Just a few suggestions. Note, disclamer. 25518 is not a licensed contractor or.

 

[rgarry]

Drill the holes on the outside, then you don't need to worry about it touching your mash

 

[Alsace]

I will definitly drill from the outside, I was just thinking about the water that might contact the foam when I am cleaning the lid after a mash.

 

[Pratzie]

I have a 10 gallon igloo round cooler and noticed a lot of heat loss. I initially wrapped the mash tun in a sleeping bag to keep the temperature stable, but I read somewhere that the lids are pretty much hollow so I drilled holes in the top and filled it with foam insulation. My first mash with the insulated top resulted in negligible heat loss over 75 minutes.

This is actually a great idea, I might have to do this too. Thanks dude!

 

[JeepDiver]

If the cooler has gotten water inside the shell and has frozen it can screw up the insulation.

 

[Alsace]

Are you talking about the outside wall or the lid?

 

[westicle]

I have a 10 gallon igloo round cooler and noticed a lot of heat loss. I initially wrapped the mash tun in a sleeping bag to keep the temperature stable, but I read somewhere that the lids are pretty much hollow so I drilled holes in the top and filled it with foam insulation. My first mash with the insulated top resulted in negligible heat loss over 75 minutes.

This ^^^

I'm building a mash tun soon and this will be the first thing I do to it if I use a cooler. very useful post

 

[jhalloran]

Thanks for the idea with the spray foam insulation. How many holes did you drill? And did you have to seal off the holes to prevent them from contacting water or are they ok with that?

The igloo cooler has raised sections that look like a Trival Pursuits wheel. I drilled a hole in the center of each one and put spray foam in them. It was my first time using it and it was way too many holes. If you are worried about water getting in you could put some sealant over the drilled out holes after the spray foam has set. It takes a day or two for it two firm up completely.

 

[seigex]

I was just having the same problem with my new Home Depot cooler I put together and used on my AG brew saturday. I went from 151 to 144 during the hour even after pre-heating the cooler. Still got my expected OG of 1.070 per the recipe, so I'm not complaining!

 

[orangemen5]

I just built a lid out of styrofoam wrapped in aluminum foil. Holds temp for the whole hour. http://i750.photobucket.com/albums/xx147/komodo66/brewquipment/discone.jpg

http://i750.photobucket.com/albums/xx147/komodo66/brewquipment/disctwo.jpg

 

[seigex]

I just built a lid out of styrofoam wrapped in aluminum foil. Holds temp for the whole hour. http://i750.photobucket.com/albums/xx147/komodo66/brewquipment/discone.jpg

http://i750.photobucket.com/albums/xx147/komodo66/brewquipment/disctwo.jpg

Very nice! Where did you get the styrofoam from?

 

[orangemen5]

Just packaging styrofoam I had laying around from offing beer equipment.

 

[Alsace]

Just drilled and filled my lid with spray foam following jhallorans idea. Of course I couldn't bring myself to drill any less than one hole per spoke. It was just too fun. Thanks for the idea, I can't wait to try this out in a few days.

 

[Dougie63]

get some reflectix and cut a couple discs that fit tightly in cooler and place on top of mash thus reducing the headspace in the cooler and it will fix your problem of losing heat