how do you raise heat from protein rest with brew in a bag?

I've found that raising the temp from ~125 to ~150 to go from protein rest to mash temp is really hard with brew in a bag (stove top mash)...

First, I have to constantly stir with heat on, or pressure builds up under the grains, and it sounds like its going to explode.

Secondly, the temperatures seem to have pretty severe pockets, and I've gotten more than 5 degree differences in readings depending on where I put the thermometer.

I noticed that Papazian recommends adding hot water to raise temp, instead of using heat. Is that what you do? The problem then is that often I'm already at capacity in my kettle for mashing.

thanks!

I don't BIAB, but you could either stir constantly like you mentioned, or boil water in a separate pot and add that to your main mash. If you do this, then you can play with the initial water to grain ratio so that when you add your boiling water it gets you to the ratio that you like to use when lautering.

Yeah, heating/stirring to avoid scorching or adding hot water and stirring are really your only options. I heat/stir on my propane burner and did the same when I brewed on the stove. It sucks, but that is a good time to enjoy some home brew.