Target Mash Temp Low - Mystery Why?

[Jiffster]

I dumped 3.5 gallons of 180F water into my 10 gallon Igloo cooler and let it sit for 10 minutes.

Checked temp of water and it was at 161.5.

Target mash temp for 8.75 pounds of grain + ~4 cups of rice hulls at ~65F is 152F.

Douhg in grains and stirred well and temp was 145F!

This makes no sense to me.

Any ideas?

I added 1 gallon of boiling water to get temp up to 152.

 

[brewpool]

Even stirring well you may find temperature variation across where you take a measurement, although I would not expect that much. What was the temperature of your grain? Room temp or was it kept somewhere cooler like a basement?

 

[Chanoc]

Maybe your strike water was not stirred and you measured the upper layer not taking into consideración the cooler water at the bottom
My opinion only

 

[Jiffster]

My grain temp was about 65. It was 66 in the basement before bringing out to garage. The temp here this morning was 38.

I did stir the strike water and the mash very well. I must have measured something wrong, huh?

 

[The_Bishop]

You need to stick a thermometer in the grain to see what it's actual temperature is. If it's colder than calculated, your mash temps will be low.

 

[brewpool]

My grain temp was about 65. It was 66 in the basement before bringing out to garage. The temp here this morning was 38.

I did stir the strike water and the mash very well. I must have measured something wrong, huh?

How long was the grain in the garage? I'm assuming the garage was the 38 degrees you mention?

Digital or analog thermometer? May need calibration.