Mash temps

I started brewing all-grain a couple of years back, and didn’t have a problem with my mash temps the first couple of times around, however I’m currently living in Utah and trying for a decoction mash on a hefeweizen. I’m using a water to grain ration of 1.25, 9.5 lbs grain to 11.8qts and I cannot hit my mash temps. One of the things that recently made things easier was the Dark Star burner, but one of the things I’m noticing is that when I add my decoctions back in, I get spots of cooler grist, and spots of hotter grist. I stir for a few minutes, and then I read it again, and the thing is just in a different spot. This even happens with my strike water, one side’s 130 and the other is 106 when I just want it all to be at 122. I have a rectangular Coleman cooler with a slotted copper manifold, which I over heat my strike water for. Does anyone have any ideas, or can anyone point me to a thread where I can figure out what I’m doing wrong? All I can think is that the elevation is screwing with me, since water boils at 204 here, or that my thermometers all suck (I have seen some 3 or 4 degree variations in all three of them from each other.)

Start by getting a quality thermometer. If you are getting bad readings, nothing else you do will matter.

Do you have any recommendations as far as a good thermometer? I have a floating thermometer, a Cromar dial thermometer, a Taylor digital probe thermometer and a Good Cook dial thermometer.

This is a certified thermometer. Guaranteed to be accurate for life.

http://www.thermoworks.com/products/low ... escription

Or many of us have purchased this certified one when it’s on “open box” sale.

http://thermoworks.com/products/thermapen/

If you have hot and cold spots, you’re not stirring enough.

Yeah, stir more and shoot for a little warmer temp to compensate for the time spent stirring. I always have issues hitting steps with decoction, I rarely bother anymore.

I may have an extra thermapen from that open box sale. PM me if you are interested. They rock.