Thermometer Error!

[justins2582]

Hi all. Yesterday I brewed up a Nut Brown Ale. This was my second all grain attempt. The first was a Red that went smoothly. After mashing and sparging this latest one, and waiting for the boil to begin I noticed the probe thermometer I used to hit all my mash temps was reading high. I left it on, sitting on the counter and noticed it was reading in the 90's!!! I made an ice water bath to check calibration and long story short, my thermometer is wack!

If this happened after all that I'm good. If not, my mash temps were 20 deg lower than they should have been. My OG should have been 1.063 and it turned out to be 1.055. My question is, how will that low of temp effect the final outcome of my beer?

 

[MalFet]

I think the fact that you were only 15% or so below expected gravity is a good sign. At a mash temp in the 130s, I would be kind of amazed if you were able to pull 55 points worth of sugar out of your grains. Can you do a starch test to see if you had adequate conversion? Did the wort taste sweet?

 

[weirdboy]

This is why I don't use those thermometers anymore. They work OK for a couple batches and then the moisture gets to them and they go bad.

 

[justins2582]

I agree that if my temp was that low I wouldn't have been able to convert as much sugars as I did, which leads me to think the main mash was probably at the correct temp. Like the previous poster said, the moisture from the mash might have been the last straw for my thermometer. I might not have gotten my sparge water hot enough if that is when it happened and that's why my OG was a little low. I don't have any iodine, which I guess I need to go out and get now. I did taste it and it was sweet. Also, my primary is chugging along like normal so I'm not too worried.

On that note, what kind of thermometers do you guys use to monitor the mash temps?

 

[02fx4dude]

This is why I don't use those thermometers anymore. They work OK for a couple batches and then the moisture gets to them and they go bad.

+1

I had about 6 brews that seemed to have been mashed to low when I started using digital thermometers. I went back to using a dial thermometer for the mash. I use the digital to check accuracy of the dial thermometer at the mash temp range though.

 

[iijakii]

You can get your expected OG even if your temperature was whack. You won't notice until you ferment. If your thermometer was 20F too high, your FG is going to finished extremely low. You'll likely have a pretty watery-tasting beer.

Sorry to be the bearer of bad news, we've all screwed up a batch or two due to a faulty thermometer

Hopefully you had made some good mouthfeel built into the grainbill and it will still be OK. You could also siphon it off of your yeast cake before it finishes too low. And carbonate a little higher than normal if it's still pretty watery.

 

[azscoob]

Try Bobby_M's method of wort-proofing a probe thermometer. It saved mine from reading off, I now use a different thermometer entirely, so the probe one was retired.

 

[carrotmalt]

I had a thermo that was off about 12 degrees and my amber ale ended up at 1.002. Extremely dry! I added a bit of malto dextrin to it and it helped quite a bit.

 

[MalFet]

You can get your expected OG even if your temperature was whack. You won't notice until you ferment. If your thermometer was 20F too high, your FG is going to finished extremely low. You'll likely have a pretty watery-tasting beer.

Sorry to be the bearer of bad news, we've all screwed up a batch or two due to a faulty thermometer

Hopefully you had made some good mouthfeel built into the grainbill and it will still be OK. You could also siphon it off of your yeast cake before it finishes too low. And carbonate a little higher than normal if it's still pretty watery.

I'm still skeptical... If he was off by 5-10 degrees, I'd be right with you (and he very well might have been), but IIRC barley starch doesn't even gelatinize until the low 140s. A beer mashed at 147F will be extremely dry like you say, but a beer "mashed" in room temperature water won't have any sugars to speak of. The question is, where is the threshold?

 

[justins2582]

Oh well, I'm sure it will still be drinkable. You live and learn. I had no idea the digital therm probes weren't capable of withstanding liquids. I figured if you could put the thing in the oven, it could take a little water.

Thanks for the replies tho. Can anyone link to a good dial therm or are they all pretty much the same?

 

[justins2582]

You can get your expected OG even if your temperature was whack. You won't notice until you ferment. If your thermometer was 20F too high, your FG is going to finished extremely low. You'll likely have a pretty watery-tasting beer.

Sorry to be the bearer of bad news, we've all screwed up a batch or two due to a faulty thermometer

Hopefully you had made some good mouthfeel built into the grainbill and it will still be OK. You could also siphon it off of your yeast cake before it finishes too low. And carbonate a little higher than normal if it's still pretty watery.

Here was the grain bill, btw:

9.00 lb Pale Malt (2 Row) US (2.0 SRM) Grain 76.63 %
1.00 lb Caramel/Crystal Malt - 60L (60.0 SRM) Grain 8.51 %
1.00 lb Oats, Flaked (1.0 SRM) Grain 8.48 %
0.50 lb Victory Malt (25.0 SRM) Grain 4.25 %
0.25 lb Chocolate Malt (350.0 SRM) Grain 2.13 %
1.00 oz Fuggles [4.50 %] (60 min) Hops 14.7 IBU
1.00 oz Goldings, East Kent [5.00 %] (15 min) Hops 8.1 IBU