Insulate your cooler lid

[johnrm]

Perlite. http://www.perlite.net

I hadn't heard of it until I spotted a thread over on Jim's.
Great for insulating the lid of your cooler.
Pour it in and seal with silicon, job done.

[Drum]

Nice one John, perfect timing with that link. I've been thinking of insulating the cover of my mash tun, and ive a bag of perlite somewhere leftover from replanting aloe vera cuttings last year. Planning to brew in the next few days so i'll do this first and report back if it helps with my temp retention.

Cheers, Ray

[johnrm]

Great stuff Drum.
I bought a can of expanding foam but never got the nerve to fill the lid of my cooler with it.
I was thinking aerobead, but static would be a nightmare.
This stuff sounds perfect.
I hate throwing quilts over coolers, but non-insulated lids mean you have to do this.

[magnethead]

Heya John, the expanding foam works perfect as long as you make lot's of vent holes on the opposite side, to the side your pumping it in .....Used it on my cooler and it holds temp perfectly

[johnrm]

I have it in my head that this stuff gets everywhere and is incredibly messy.

[DEMPSEY]

The secret to using expanding foam is to underfill the cavity. The foam continues to expand and will overflow the space which is no problem because when it sets you simply use the wife's finest kitchen bread knife and trim the excess. It does not stick to the surface or the knife when you do this so she will never know . (unless she see's you )

[Will_D]

I have it in my head that this stuff gets everywhere and is incredibly messy.

Well dont stick the Fekin tube in yer ear!

[Drum]

OK, I filled the lid of my mash tun with perlite the other day. Definitely helped with holding temp during the mash, I lost about 2 degrees over 70 minutes which is about normal for me except that the kitchen was a lot colder than the last time I brewed (11C compared to 20C) and I had removed the cooler box from the aldi cold bag it usually lives in. I bumped into the mash tun the last time I brewed and splashed some wort down the inside of the bag and of course I forgot to clean it out so it had some mould growth when I went to use it again.
So in short I got the same temp retention with less insulation than usual in a colder room, result.
Once I get another freezer bag to put the tun in I think this will hold temp perfectly.

A few warnings tho. Perlite is VERY dusty, it's meant to be wetted in the bag before use with plants but I didnt want to put it in the lid wet so I ignored that bit. If anyone else is going to try this do it outdoors, keep your head upwind and/or wear a dust mask. Also, I used a funnel to put the perlite in the lid. At first I just poured straight into the funnel but it clogged up fairly quickly. I ended up having to drop the perlite in slowly by the handfull so it didnt clog the funnel.   

[johnrm]

Thanks for the update Drum, good job!