Bad Thermo, Bad Mash, still ok?

Bought a digital thermo for my batch last weekend, so I could mash with more precision. It seemed to work fine as that batch fermented vigorously for 5-6 days with blow off and now has an airlock bubbling every 10-15 sec. I brewed again this Friday night and get my mash to what I though was a precise 154 F. While that was sitting for 60 min I was heating my sparge water. In that process I got side tracked in conversations with friends, came back and the thermo says that water is near boiling. I cool it down to 190. I decided to put the backup thermo for kicks and it's significantly cooler than the digital thermo. I go to measure my mash temp with old thermo and it measures a mash temp around 125-130. I verify this with another meat thermo. So what to do? I warm the sparge water to 190 asap. Drain half of the mash and add sparge water, mix good and let sit for 10 min in the high 150's. I sparge after that with 180 F water and proceed with the boil. 8 hours later and there is little fermentation occurring.

Is this a lost cause?

Has anyone ever experience a defective thermo like this? Next time I plan to buddy check my thermos for the mashing process.

Thanks all!

Did you do an OG reading post-boil? Were you close to you target?

What type of yeast are you using? Not having active fermentation visible after only 8 hours isn't too unusual...

Always check that your thermo is spot on at both icewater and boiling temps before you use it for brewing. OK, that doesn't help you now.

The problem is that the real workhorses of the enzymes (alpha and beta amalayse) work in the high 140's to high 150's. It takes about 30-60 minutes for this to work. You had two issues. First, you drained off wort that had a lot of the enzymes in solution and then diluted the remaining enzymes with fresh water. The fact that it only sat at the correct saccrification temp for 10 minutes means you probably didn't fully convert to sugar.

If I had the chance to advise you while it was happening, I would have suggested drawing off about 2 gallons of mash and bringing it up to about 165F and then recombining with the mash. Even what you did would have been OK if you would have let the mash sit for at least 45 minutes in the 150's rather than 10 minutes.

I don't know if it's a lost cause but I'd say there's a good chance.

I don't have a lot of experience with thermos that are *not* defective.

You'll probably be ok. If the wort tasted sweet and ran clear, you've got sugar water. Your efficiency may be low since you effectively did a long protein rest and just a 10-minute conversion rest.

well.. It's hard to say where or when this happened. Was it aways low and the first batch is the same as this one would have read, Or did this just occur and only effects this batch?

I found out the best way is to use a certified lab grade thermometer for calbrating your other thermometers with. If a float thermometer reads 6* different then the dgital one which is correct? normally you would think the new digital thermmeter would be, but that doesnt always hold true.

Did you take an OG reading afterthis batch was boiled and cooled?

This may help comfort you a bit. I recently learned the thermometer I was using for years reads 15F hotter than truth. I still made great beer, even though my temps were way off. I am sure there was some luck in my experience.

I now use 3 thermometers and I take a little vote in my head which is closest to accurate.

Thanks for the responses. The OG was 1.058 or so, but estimated at 1.064, so low, but not that far off. It is starting to ferment, some light krausen developing, but the Nottingham I'm using has activated much quicker for all previous batches, so Bobby may be correct an there is just a lack of fermentable sugar to do much. I'll wait it out a few days and take a good lesson from this experience.

I think the thermo was correct for the batch last week, or at least the mash part. I water-bathed my carboy for fermentation last week and the initial temp as fermentation ramped up was 82 F, but the room temp was in the 60's. I added frozen water bottle and the temp only dropped to 69 F. I thought it was strange that the temp was not lower, but did not double check, so I think the thermo was bad at that point. The positive is that my beer last week probably ramped up to 70 F, but I got it down to a steady 60 F for most of the fermentation.