Mash Tun Temp Problem

[Maxt]

I have just made a mash tun out of a 36L esky. I had used this esky once before for a partial, and I thought that it didn;t hold it's temp because of the low grain to size ratio ( as well as no preheating).

My first AG with it was not much better. It held it's temp ten minutes into the mash, (I pre heated with a few litres of hot water), but it still lost 6 degrees over 90 mins. Is this unusual?
Would insulating it (blankets, camping mats etc) majke any difference?

 

[Bijengum]

I have just made a mash tun out of a 36L esky. I had used this esky once before for a partial, and I thought that it didn;t hold it's temp because of the low grain to size ratio ( as well as no preheating).

My first AG with it was not much better. It held it's temp ten minutes into the mash, (I pre heated with a few litres of hot water), but it still lost 6 degrees over 90 mins. Is this unusual?
Would insulating it (blankets, camping mats etc) majke any difference?

Depends on what brand it is - I have found some of the cheap ones as usless as...

Any extra insulation will definately help.

 

[Hogan]

I have just made a mash tun out of a 36L esky. I had used this esky once before for a partial, and I thought that it didn;t hold it's temp because of the low grain to size ratio ( as well as no preheating).

My first AG with it was not much better. It held it's temp ten minutes into the mash, (I pre heated with a few litres of hot water), but it still lost 6 degrees over 90 mins. Is this unusual?
Would insulating it (blankets, camping mats etc) majke any difference?

Hi Maxt - the better insulated your MLT the less the temp will drop - obviously. Most eskys with a little help will hold temp through a 90 minute mash to a loss of 1c. It is also helpful to use Beersmith or Promash to determine what your strike temp should be set at. i.e. takes into consideration what your tun is made of - metal, plastic etc. and sets the proper temp.

Consider this for better insulation. Sit the esky on a thick sheet of insulation foam.
Cut a rectangle of foam and fit it into the esky so its sits snugly on the grist during mashing. This will stop temp loss in the tun headspace.

Cheers, Hoges.

 

[domonsura]

You could try wrapping it all up in a cheap blanket maybe, I know those cheap polarfleece blankets from BigW work OK as a last resort (but don't make the mistake of letting the missus see that you've nicked one of her blankets to do it )
or you might be able to compensate for the gradual temp loss by doughing in thick (less water), so you can add more water to adjust the temp as you go along a couple of times during the mash, maybe at 15-20 mins add enough to bring it back up to desired mash temp and give it a quick stir, and do the same thing at 30 mins and 45 mins. You'll have more water in the mash at the end maybe than normal, but I've done this myself a couple of times, and it worked fine but was a bit of a pain.
Good luck!

Maybe a bit of both, or maybe just scoring a better esky?

Hogan is right too, getting the strike water temp right is most important, if this isn't right nothing else will be. Maybe also consider pouring a jug of hot water into your esky and closing up for 5 mins before emptying and putting your grain in (to pre-warm the esky)?

 

[Tony]

I used to use an esky and found it lost a few deg.

I made a piece of foam that was about 1 to 1.5 inches thick that pushed down onto the top of the mash to hold the temp in.

It worked great and only dropped about 1/2 to 1 deg at the most on a cold morning after that.

I only mash for 60 minuites and it your using modern good quality malts thats all you need.

here is a pic

cheers

 

[Maxt]

Thanks for all the tips. Will give the foam a go, as well as wrapping the bugger up!

 

[winkle]

Did you pre-heat it first? there's a lot of cold plastic to rob you of heat. I've got a cheap keep cool cyclindrical that maybe loses 1C over 60 to 90 minutes, but is hopeless if not pre-heated.

 

[Wortgames]

Are you taking into account the mass and initial temp of your grain?

Also, avoid draughts - the more turbulent the air is around the esky, the better the heat exchange between esky and air (although the esky should be doing a better job than it is). If you've got a sheltered corner (or a cupboard) somewhere then try that.

 

[Cortez The Killer]

I use a sheet of polystyrene and and 44L willow mash tun and it holds it temp nicely - maybe loosing 1*C over an hour mash

Cheers

 

[Jazzafish]

If you heat your water using a hand heeld element, heat it in the mash tun... found that worked well before I started underletting.

Here is a bit of help for strike temps for a 5kg grain bill mashed at 66*C with 15 litres of water (3:1 Water to Grain ratio) ... using promash.

Grain temp / Strike temp

13 / 73.33
17 / 72.78
20 / 72.22
22 / 71.67
26 / 71.11
30 / 70.56
34 / 70.00

 

[Maxt]

Found I had an esky lid that fitted snugly inside the mash tun. Used this as well as wrapping the tun in a thick sleeping bag. Lost 2 deg over the mash. Woohoo.