Last night I brewed for the second time, an all-grain American Wheat beer. Everything thing went really smoothly and I hit my OG number okay.
But there's something about the mashing I didn't quite understand. I was tracking the mash temp with a probed thermometer : http://www.amazon.com/Taylor-1470-Digital-Cooking-Thermometer/dp/B00004XSC5/ref=sr_1_1?ie=UTF8&qid=1330111438&sr=8-1 (which I thoroughly recommend to anyone who is still using the floaty style thermos!!). To my delight, the first 20-30 min. of the mash, I stayed at 151 F, 1 degree below my target 152 F. Around 35 to 40 minutes in, it dropped to 150 F so I boiled a quart of water and dumped it in and stirred it around. To my surprised, the temperature dropped to 149 after a few minutes and as I boiled another quart, it dropped to 148.
Was the probe just in a warm spot? Or did me opening the cooler affect it that dramatically? I also noticed my mash paddle was sitting on the sink, so maybe it was cool, too. Is a 3-4 F drop in temp so bad this late in the mash?
I'm sure my brew will turn out, but I just got to thinking about this stuff and would like your thoughts.