Mash out not raising my temp

I'm in the process of taking my first running right now. This is the second time I've used a mash out, and it's the second time it hasn't raised my grain bed temp. I mashed in 11.38 lb of grain with 14.25 qt of water, hit my mash of 154 dead on, and it even stayed there for an hour. I then added 2 gallons of water at 198, waited ten min and started my running. Just before running I measured the temp and it was only at 157.
Any ideas why, or what I could do to fix this without adding boiling water?

Common sense question (but we all miss stuff like this), but did you stir thouroughly after adding the hot water? If not, the entire grain bed is not going to heat the same.

yeah, I stir, let it sit for 5, take temp, wait 5, then drain.

Three suggestions:

How did you add the water? If you just pour it in, you won't lose much heat in the transfer. If you use something to ladle it in, you will lose a bunch of heat.

If you're like me, you preheat the mash tun before doughing in and set the thermal mass to 0. This screws up the mash out calculations. I just heat more mashout water than I need, add some, check the temperature, and add a bit more based on what the temperature is. Takes a few tries to get it right, but if you end up between 165 and 170, it seems to work well.

If you leave the lid off, then a lot of heat is going to escape, but I should think it is very difficult to stir with the lid on.

-a.

I just ran your numbers through beersmith and it showed 168F mashout using your numbers. I used 5 gallons for a batch and 6 gallons preboil. You must not have stirred enough when you measured the mash after the 2 gallons 198F water was added. Always stir well just before the reading. There's just no way you would have only a 3 degree rise after adding 2 gallons at 198F.

My first couple of AG batches I thought my temps were screwed. I later figured out my thermometer was junk. A $25 instant read does a much better job than the POS I was using.

I stir, wait five minutes, and take my reading after each infusion/adjustment. In my rectangular cooler I have to poke around to get 3-4 readings and average them, there are always warmer and cooler spots.

- Eric

Another thing that could have happened was that you really lost more heat through the mash than you thought. If you measured the temp at the core of the tun, it could be 154 while the areas near the walls are 148. That would account for the lower equalized temp.