Continuing Strike Temp issues BIAB

I continue to have issues with my BIAB strike temp meeting my desired mash temp after mashing in.  Frankly it barely drops... 

Beersmith 3.0
Desired Mash Temp 152.1
Mash Tun 15gal and 12.25lbs
Stainless 0.12 Mash Tun Specific Heat.

With Adjust Temp for Equip ON
Strike Temp 160
With Adjust Temp for Equip OFF
Strike Temp 158.7

Actual Temp after mashing in 157 (Using Strike Temp ~160)

So it fell ~3-4 degrees F.  I will in the future turn off Adjust Temp for Equip, but that's still going to leave me off by a few degrees.

On some older post it was suggested to adjust the thermal coefficient (I believe that's the specific heat) but again that will only have an impact if if I leave that setting ON.

Typical procedure.  I heat up my strike water to temp and let it sit for ~3-4 minutes to ensure it's stable.  Not still rising due to being on the burner.  Then I mash in and again wait a minute to allow the temp to stabilize before wrapping the Pot/Mash Tun with thermal insulation.

I suppose there could still be an issue with residual heat form the propane burner and I may need to take the pot off during the mash?

What is your grain temperature set at and did you measure it before mashing in?  Mash tun temperature setting?

With BIAB, you are better off having the mash tun temperature set to the target strike temperature when having the 'adjust temp for equipment' turned on.  This will allow the program to use the weight and specific heat of the mash tun when considering the temperature drop.  When you do this, then the specific heat of the mash tun will make a difference, generally not much since the temperature drop is not great, but a few tenths of a degree. 

Just playing around quickly with my 10 liter set up, it made a 1.2 F degree drop in my strike temperature just toggling my temp adjust on and off and setting the strike temp target for the mash tun temperature. 

Add this 1.2 onto the 3-4 degrees and you should be a lot closer to your intended mash temperature.  You should be able to fine tune it from there.

The three best things you can do in Beersmith to get a more accurate strike temp is to have a custom equipment profile created... uncheck the adjust temp for equipment box and take the temperature of your grain and enter that into the mash step. You also want to have a mash profile created for BIAB.

https://youtu.be/VKiEjhxo2oo