One thing about brewing that stresses me; mash temp. I use the formula, typically having a strike temp of around 160F with 9 gallons of water BIAB to shoot for low 150's. In the end this seems to work once I drink a brew and chill but I'm bothered by the fact that when I stir the wort i get readings all over the place. I can get anywhere from 145-158F. When I leave the probe roughly centered and don't stir it reads ~152F. I don't understand what is going on in that magical brew pot. Is there some kind of thermal dynamic hocus pocus going on or what?should I not stir and just go by the center temp? Does the grain inhibit convection cells? When I try to keep the entire pot constant it just stresses me out maintaining low 150's. Any thoughts? Thanks.