I’m still learning to drive my new heated mash tun. With today’s brew session, my temps held well at 152-153 for about 30 minutes. When they dropped around 150, I decided to add a little heat and stir while doing so. Nothing happened and the temps dropped more, down to 142. I turned the burner up, stirred more, the temps dropped more. Then suddenly, the temp rocketed to almost 180, in about 5 seconds.
So obviously, there was something screwy with the thermometer in the mash tun. I checked the temps with another thermometer I trust, and it was around 165. I quickly added 1.5 gallons of cold water and dropped the temp back to 152.
Is this wort “dead”? Did it essentially mash-out (after only about 30 mins of mashing), denaturing the enzymes needed for starch conversion? Should I continue with this batch?
From my experience I would say you should be alright. This sort of thing used to happen to me when I tried adding heat to the mash in my kettle. And never ruined any beer.
I still use my old kettle as my mash tun, but no longer add heat with the burner. Adding hot or cold water alwyas works much better.
I would say if you are doing a 60 min single infusion, you usually would not need to add heat. Lock in your strike temp, then keep the tun insulated (I wrap my kettle in a sleeping bag. I rarely even lose a degree. If you do lose 1 or 2 degrees over 60 min it will not be an issue.
Just opening the tun to take temperature readings can lose you some heat, so I say leave it alone.
Thank you, Brew Meister Smith. I’m feeling a little better after reading your reply. I think your suggestion of not heating will be the best way to go if I can find a good insulator. I like the sleeping bag idea. And I definitely will run some tests on this damn mash tun thermometer.
I’m afraid my Scottish ale will be a little sweeter than it normally would have been, though.
