Now how would this apply to a direct fired RIMS setup? Of course I stir when doughing in and recirculate after I get it all the grain in the mash tun. I like to compare my two thermometers. One is a bimetal and one is a floating. They read the same when I am heating my strike water. Once I start the mash though it isn't unusual to have a difference of 6-8 degrees F even after stirring/recirculating. I think part of my problem is that the probe on the bimetal doesn't go deep enough into the mash, only an inch or so, and it usually reads on the low end. I do wonder though how easy it is to get a truly uniform mash temp and what is the effect of mash temp variance. Do the enzymes care that some are at 150 and some are at 154? That is why I just shoot for a range of mash temps say 150-152 and call it good.