Expanding foam for round cooler lid?

[sea2summit3]

I've converted an older round drink cooler into a mash tun. The lid has a vent on the inside that leads out to a tiny hole on the rim. I assume this is for pressure equalization, but am concerned about losing too much heat through it during a 60 min mash. I've noticed that some others on HBT have filled there lids with expanding foam for added insulation.

1) Did any of you foamers notice a difference in holding mash temps?

2) Since I've got this vent hole, I'm concerned about the foam's chemicals leaching back into the mash tun after steam condesates through the vent hole. After reading some other threads, is expensive, food-grade, special order silicone caulk my only option?

 

[MacBruver]

I wouldn't worry about the hole much- I did a 90 minute mash with 24 lbs of grain in it, and it lost hardly any heat at all (as measured from the top, where it would stand to lose the most). Maybe a couple of degrees.

 

[sea2summit3]

Cool... I'd rather not go through the trouble if it will hold heat without modifications. Thanks!

 

[wilserbrewer]

preheat, preheat, preheat

Add your strike water plus 10 and wait 10 minutes or so for the cooler to heat up, I use a coleman w/ a hollow lid and I'm not bothered.

 

[sea2summit3]

preheat, preheat, preheat

Add your strike water plus 10 and wait 10 minutes or so for the cooler to heat up, I use a coleman w/ a hollow lid and I'm not bothered.

Thanks for the advice!

 

[wilserbrewer]

OK check...you are in Nevada...all bets are off if you are mashing outside in sub-zero conditions...cheers

 

[jds]

I have a 5 gallon Igloo cooler that I use for small mashes (up to about 14 lb of grain). The lid's hollow, with a hole for my thermometer probe. Coldest brewday yet was about 18F at mash-in, and I lost about a degree over the hour.

I say, try your tun first, and if it holds temperature acceptably, why bother with foam?

 

[sea2summit3]

I had my first AG brew day with the MLT and it lost about 3 degrees. The lid has a couple cracks in the top so maybe I'll try sealing those up firt before I get to crazy with foam. Thanks for the suggestions!

 

[Scut_Monkey]

I use a rectangular shaped 48quart cooler. It had rather bad insulating properties so I thought spraying some foam in the lid would help. It did. I get about half the temperature loss now. However, I have used a round cooler before and it held temperature better in general.

 

[sea2summit3]

I use a rectangular shaped 48quart cooler. It had rather bad insulating properties so I thought spraying some foam in the lid would help. It did. I get about half the temperature loss now. However, I have used a round cooler before and it held temperature better in general.

I figured it would help. If I end up going that route, I guess I'll prep the vent hole with some silicone sealant so I don't get any chemicals from the foam leaching back in. I did have a lot of airspace in the tun from only brewing about 11 lbs of grain. Maybe that aided to my 3 degree temp loss as well.

 

[Scut_Monkey]

Yeah if you have a lot of headspace it does tend to drop your temp. Like someone else mentioned preheating the mash tun is very important. Also, when you have a lot of headspace its best to make sure the mash is very well mixed initially put the lid on and then let it go with no stirring or maybe stirring it once. However, the foam does help to some degree. Though I would think it would be less effective for a round cooler as they have less surface area/volume for the lid than my rectangular cooler. To seal it I would simply use some kitchen grade silicone. I never even sealed the holes I made and I'm not worried about it.

 

[sea2summit3]

I preheated my tun but it cooled down quite a bit before I was ready to go. But all in all, my first AG batch went really well and gave me some ideas for more tweaking of my equipment.
From what I'm finding on the internet, I want a "NSF certified" silicone sealant. Doesn't look too expensive. Hopefully I can find it at HD or somewhere else locally...

 

[Hermit]

Saran wrap type material would be quick, dirty (well clean) and inexpensive. Just a quick layer or two over the thing before you close the lid.

I've converted an older round drink cooler into a mash tun. The lid has a vent on the inside that leads out to a tiny hole on the rim. I assume this is for pressure equalization, but am concerned about losing too much heat through it during a 60 min mash. I've noticed that some others on HBT have filled there lids with expanding foam for added insulation.

1) Did any of you foamers notice a difference in holding mash temps?

2) Since I've got this vent hole, I'm concerned about the foam's chemicals leaching back into the mash tun after steam condesates through the vent hole. After reading some other threads, is expensive, food-grade, special order silicone caulk my only option?

 

[rico567]

I use the Rubbermaid / HD 10 gal. "big orange" cooler. Filled the lid with the "Good Stuff" expanding foam insulation available just about everywhere around here. Don't know if the insulation CAN leach, but with this cooler, it doesn't matter. No holes on the inside, I drilled 4 holes around the outside edge of the lid (which is outside the threads, so nothing can get into the cooler from there), filled it with insulation, and now I only lose maybe 2 degrees in an hour's mash.

 

[ChshreCat]

I found a folded up bath towel on top of the lid helps with my heat loss.

 

[mmb]

I use the Rubbermaid / HD 10 gal. "big orange" cooler. Filled the lid with the "Good Stuff" expanding foam insulation available just about everywhere around here. Don't know if the insulation CAN leach, but with this cooler, it doesn't matter. No holes on the inside, I drilled 4 holes around the outside edge of the lid (which is outside the threads, so nothing can get into the cooler from there), filled it with insulation, and now I only lose maybe 2 degrees in an hour's mash.

If someone does this, using the "Good Stuff" window formula foam so that it doesn't expand too far and is no longer able to screw on if you use too much.

That stuff really expands...

 

[Hammy71]

I found a folded up bath towel on top of the lid helps with my heat loss.

Same as cat.... I pre-heat and wrap an old flannel shirt over the top of the cooler and tie the arms around the seam between cooler and lid...

 

[ChshreCat]

Same as cat.... I pre-heat and wrap an old flannel shirt over the top of the cooler and tie the arms around the seam between cooler and lid...

It's like, giving your mash tun a big hug!

 

[sea2summit3]

After another AG batch it seems to be holding temp well. Think I'll skip the foam! Thanks for the advice!

 

[Cpt_Kirks]

For my 10 gallon water cooler MLT, I made an "internal lid".

I cut a piece of 3/4" foam board to fit snugly into the cooler, with a loop handle made of a cable tie. When I use it, I wrap it in saran wrap and dip it in star san foam. The lid floats on top of the mash.

Using both lids, I lose less than a degree in an hour long mash.

 

[sea2summit3]

For my 10 gallon water cooler MLT, I made an "internal lid".

I cut a piece of 3/4" foam board to fit snugly into the cooler, with a loop handle made of a cable tie. When I use it, I wrap it in saran wrap and dip it in star san foam. The lid floats on top of the mash.

Using both lids, I lose less than a degree in an hour long mash.

That's an great idea! Do you find that any mash water leaks between the saran wrap to the foam board?

 

[Cpt_Kirks]

That's an great idea! Do you find that any mash water leaks between the saran wrap to the foam board?

I don't even know if the wrap is needed, but I use multiple pieces of it and overlap them. I haven't noticed any leakage.

 

[sea2summit3]

I don't even know if the wrap is needed, but I use multiple pieces of it and overlap them. I haven't noticed any leakage.

Thanks for the tip.... I'll give it a try!