Thanks for all the replies. Sounds like I should consider changing my setup a bit. Currently when I'm heating from mash to mash out I suspend my bag just off the bottom of the kettle to avoid burning it. As a result, the grains are held tightly together (until temp is reached and bag is let loose again) and there's not much room to stir. Probably not ideal. This is a stovetop size setup, about 4 lbs of grains and about 3.5 gal of water at time of mash.
Sorry for the disruption to the OP.