Overshooting target mash temp

[Frenchy]

I keep overshooting my target mash temp. I'm using 2 methods to determine the strike water temp. John Palmer's "How to Brew" book, as well as Brew Mate's strike temp calculater. Both are withing 1/2 degree F of each other.

I use a 10 gallon rubbermaid water cooler. and preheat with 1 gallon boiling water. And I do dump that prior to mixing my grain and strike water.

When I mix them and let sit for a couple minutes, it usually looks ok. But when I go to stir again in about 10 min it usually reads higher than I wanted. Is it possible that I'm over doing the preheat, and that is putting more heat into the grist after I've mixed, or is it just more likely that I've really got more heat in my water that I realized when I shut the burner off?

 

[Gartywood]

I no longer do the tun preheating step. Software will account for the thermal mass of the tun in the strike water calculation. IMO its an extra unnecessary step.

 

[Yooper]

An easy way for me to not overheat (or undershoot) the MLT temperature is to add the strike water at 180 degrees. Let it sit until it's at the correct strike temperature, and then dough in.

That preheats the MLT, but means there is no direct heat to change the temperature.

Also stir well when you add the grain. Stir some more. Then, check the temperature in several different places. If it's different, stir some more. You want the temperature to be equalized throughout the mash. Then it should stay put.

 

[tally350z]

^^^

That's what I do as well.. Never have an issue hitting mash temps.

 

[rohloffj]

You could do a test, with a common amount of strike water, and see how much heat your MLT will absorb. Similar to what the others are saying, but with a little more Scientific Method applied

 

[Pappers_]

An easy way for me to not overheat (or undershoot) the MLT temperature is to add the strike water at 180 degrees. Let it sit until it's at the correct strike temperature, and then dough in.

That preheats the MLT, but means there is no direct heat to change the temperature.

Also stir well when you add the grain. Stir some more. Then, check the temperature in several different places. If it's different, stir some more. You want the temperature to be equalized throughout the mash. Then it should stay put.

Great idea!