Keeping the mash at a certain temp.

[mark68]

After seeing a few photographs of people mashing in a plastic esky,how do you control the temp. as there is no heat source apart from boiling a pan full of water and adding this to the mash?It would seem that a variation in temp. of 20 degrees or more over the period of the mash doesn't ruin the brew.Is this correct?

[gregb]

Pre heat the esky, it usually holds close enough.

Cheers,
Greg

[General]

Greg,

I am also interested in this, so are you saying heat the esky with boiling water? or some other heat source?

[munkey]

i have a temp controlled mashing pot and dont use the coolbox type, but i do occasonaly use an infusion method to better control the temps, bacicaly i use the Decoction mashing technique to acheve tempriture additions, this is bacicaly just removing some of the mash and boiling it then adding it back, there is a specific science to calculating the amount needed to be drawn off and heated to acheve your temp adjustment. (there are programes and guids that tell you how).

[gregb]

General,

Spot on, hot water into the esky to warm it up, same as you do when you pre heat a thermos flask.

Cheers,
Greg

[Bruiser]

Mark 68, you should only experience a loss in temperature of a degree or two, not 20 degrees. That's why people use esky's as mash tuns; they're designed to not lose the cool temperature from the ice to keep your beer cold. Put hot wort into it and the insulation keeps most of the heat in.

[wee stu]

Bruiser is right, especially in a full mash brew there is a lot of thermal mass in the grain itself. If you have an esky which loses 20 degrees over the duration of a mash, go and get another esky.

I use a 35l cylindrical Keep Cold brand esky, and with a 60 minute mash and around 5kg of grain, I tend to lose a degree only over the mash period.

[yardglass]

same, the mash temp drops 1*C over 60 min.