Mash Tun Loosing Heat

[topcat2006]

Hi,

I've just finished building my AG Brewery. For my Mash Tun I have used a 25L Coleman Coolbox of undetermined age.

On my "Dry" Wet Run to work out liquid and heat losses I have lost 6 Deg C over 1 hour at the mash tun. I cannot feel any heat loss on the box itself so I don't know how much of an effect wrapping it in an old sleeping bag etc will have.

My water going in was 70 Deg C and I measured 66 Deg C in the mash tun prior to putting the lid on.

How important is it not to loose temperature - or do I simply start off with a higher temperature knowing I will lose 6 deg c over the hour. (So if I want 66 Deg C, make sure it is 72 Deg C on the way in)?

Thanks

Tom

 

[dennisking]

Did you pre heat the tun. A couple of kettles of boiling water and leave for 15-20mins will help.

 

[Growler]

I have also read that once you have the grain in it helps with heat loss

 

[dennisking]

I have also read that once you have the grain in it helps with heat loss

Definitely

 

[topcat2006]

I did warm it with the 70 Deg C water prior to putting the water in but not boiled water.

TBH I did wonder about the mash helping retain the heat - and also that I may have under-filled the Mash Tun in comparison to the level of water + Grain.

Thanks

Tom

 

[Sean_Mc]

I use to leech heat out of the bottom of mine, so used to stand it on polystyrene from Mrs Mc's printer packaging.

A layer of tin foil on top of the mash also helps.......second time today I've advised using tin foil for different applications, I don't have shares in it, honest

 

[Springer]

Tops of cool box are also short of insulation, heat rises to the top as we know and away it goes. Been meaning to drill a hole in mine and inject some insulation.
Had a similar problem when I built my heated cupboard, when I tested it empty, heating air, it was not very impressive to say the least, but once it had a couple of 25 litre brews in there it was a different matter.
S

 

[topcat2006]

I've already injected some foam into the top as could see no insulation on it.

I might inject some foam round the sides as it's all polystyrene - but saying that I could not feel any heat on the sides and to which suggests to me it's not loosing heat.

I'll try a proper run next weekend and see what happens....

Tom

 

[craigite]

I have mine wrapper in camping mat material and sat on top of a polystyrene base about an inch thick. A towel over the top helps too.

Grain in the tun will help a lot.

 

[Ceejay]

On my first brewday i used a cheap sleeping bag to cover the tun and lost no heat whatsoever over 90 mins. Yesterday's brewday was done sans-sleeping bag and I lost 4 degrees! :shock:

 

[robsan77]

i use a sleeping bag and a pillow on top. Works well for me. It looks like I am going to have a load of expanding foam left over after putting in my windows (my measurements are a bit tight, not much clearance). So I am going to build a massive foam shell for my tun wrapped in a camping mat. :thumb: