Foam insulation in contact with mash

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Judochop

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I was introduced to the idea of laying foam insulation on top of the mash for better temp control in another thread. (And who wouldn't be interested in better temp control!)

But I want to know if anyone knows of any legitimate concerns with foam insulation being in contact with the mash. And if it is wiser to keep the plastic cover on or to remove it.

Is it safe?
 
I'd use plastic, or wrap the foam with plastic wrap and tinfoil. Not so much for contamination issues, but for the mash absorbing up into the foam and water logging it.

Plus some (most) foams aren't really intended for food contact. Thus, they may contribute some off-flavors.
 
I wouldn't do that. Better off just covering whatever mash vessel you're using with an old comforter or something.
 
I wouldn't do that. Better off just covering whatever mash vessel you're using with an old comforter or something.
The idea here being to eliminate the effects of dead air space within the mash vessel to a significant degree.

As a practical example, I'm thinking of upgrading from my 36 quart xtreme cooler to a 62 quart model to be able to do the occasional 10 gallon batch or the monster 5 gallon batch. But there's a whole lot of dead air space in a 62 quart cooler when I'm only doing a 5 gallon batch of a low gravity beer, and I imagine this will always be a detriment to maintaining mash temp. Preheating the cooler for a 5 gallon batch would be a challenge too, since I'd need to be using a lot more water to preheat than I'd need to mash. If I could close off that air space within the cooler with some kind of insulatated barrier, I'd think I'd only have to preheat with whatever mash water I needed and would be able to lock into within a degree over the course of a 60 min mash.

Wrapping foam insulation with a food grade substance of some kind seems to be on the right track. I'd like to probe the clever minds of HBT for some good ideas. (Aluminum foil and saranwrap both good ideas?)

In general, what are folks with oversized mash tuns doing to maintain their temps?
 
In general, what are folks with oversized mash tuns doing to maintain their temps?

I have the 10 gallon round cooler mash tun, usually when I have some headspace, I preheat the tun with ~185 F water and wait until the water cools down to the strike temp. Usually this takes 5-10 min, so I'd definitely suggest an adequate pre-heating of your tun. Especially for a large cooler.
 
The idea here being to eliminate the effects of dead air space within the mash vessel to a significant degree.

As a practical example, I'm thinking of upgrading from my 36 quart xtreme cooler to a 62 quart model to be able to do the occasional 10 gallon batch or the monster 5 gallon batch. But there's a whole lot of dead air space in a 62 quart cooler when I'm only doing a 5 gallon batch of a low gravity beer, and I imagine this will always be a detriment to maintaining mash temp. Preheating the cooler for a 5 gallon batch would be a challenge too, since I'd need to be using a lot more water to preheat than I'd need to mash. If I could close off that air space within the cooler with some kind of insulatated barrier, I'd think I'd only have to preheat with whatever mash water I needed and would be able to lock into within a degree over the course of a 60 min mash.

Wrapping foam insulation with a food grade substance of some kind seems to be on the right track. I'd like to probe the clever minds of HBT for some good ideas. (Aluminum foil and saranwrap both good ideas?)

In general, what are folks with oversized mash tuns doing to maintain their temps?

Have you just considered keeping your 36 quart MT for the smaller batches? I'm very averse to adding something that isn't food grade into my brew equipment, and foam seems like a risk due to sugars getting into the air pores. Foil and saran wrap aren't going to keep wort out of it, but if you could get something that you can shrink wrap onto it, that might do the trick.
 
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