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Check your thermometer everyone

I made two batches of beer and couldnt get the fermentation to take off. My OG was right on but couldnt get more than a couple of points movement. Driving me nuts.

I kept thinking my yeast management was bad. I also had this raisiny fruit funk to the beer

Then…I decided to check my thermometer and found that according to it water boiled at 170 degrees. Meaning my actual mash temps were way too high. I couldn’t believe I was so stupid and didn’t think to check it

Questions if I may. Does this make sense that the beer wouldnt ferment properly even though the OG was ok and also prove that I would get a raisin type flavor due to high mash temp. Next any recommendations on a good thermometer for a dummy?

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These things are pricey but awesome. https://www.thermoworks.com/Classic-Thermapen?gclid=EAIaIQobChMI_L-GzuuF7QIVk4CGCh09Eg4aEAQYByABEgJsHvD_BwE

Also, Damien has a post just about this… From a long time ago…
I think a Brewer should find a few times a year to verify thermometers AND hydrometers…
If boiling happens at 170*F… I think then the mashing was at a very low temp… But then, there may other variables…
Sneezles61

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I’m thinking it’s the opposite and I may not have explained well. . If water boils a t 212 and the reading on the thermometer was 170 then my mash reading of 150 per that thermometer would mean the actual temperature was considerably higher than the thermometer indicated. Yes?

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If your OG was spot on then it should have fermented regardless of your thermometer. Your OG would not be spot on if it was your faulty thermometer because your mash conversion would have been messed up because you would have denatured your enzymes.

Thank you Squeegee… And Chris… I think you are right about the temp… A couple of these SN Torpedos… and the thinking process seems to be waning…
Sign up for Thermo works offers… Even there lollipop are traceable, or close to it… They are more affordable… I’ve got the MK2… Cooking… Checking to verify my brew stuff is accurate… Indespendible tool!
Sneezles61

If he mashed high, but not to the point where enzymes denatured, he would still likely hit gravity targets but have a wort with a lot of long chain fermentables. Depending upon yeast strain used, these might end up not being attenuated.
OP does not mention if final gravities were met. If they were met, then I can get on board with your answer,

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My OG was 1.06 and final was 1.04. My understanding is that for a mash temp that is too high, it still converts to sugar, hence correctly measured OG, but that those sugars become a challenge to convert resulting in a high FG. I would appreciate clarification on that…I hope that’s correct because I have no clue otherwise. Yeast was healthy, pitch temps and ferment temps were good. Same grain supplier and crush. I don’t know what other variables there could be.

Podcast #14, mashing… Charley Bamford (?) on Beersmith… Been a long time ago since I’ve listened… Might be good to revisit…
Sneezles61

OG 1.06 and FG 1.04? Did you mean that?

What yeast strain was used?

About 2.8% ABV…
Sneezles61

Good point but if 170 = 212 then his was target of 150 would have actually been around 187 and he should not have hit his target spot on.My understanding is that Alpha Amylase (the heartiest of Ases) denatures at 170F

I wonder if even for a short time, conversion happened… before it was over heated and died (denatured)…
Sneezles61

Totally agree with you. This is a puzzling situation.

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Oof. I feel your pain. I had a thermometer problem on a batch this summer. I wanted to use one of those infrared “laser” type of thermometers. The evening before brew day, while cleaning my brew kettle, I checked it against two other thermometers: the one installed in the kettle and my old buoyant mercury thermometer. Everything seemed to check out, and I thought man, this infrared thermometer is gonna be AWESOME.

The next AM, I got the ball rolling and started heating up the strike water. Monitoring my water temperature with the infrared thermometer, I hit my strike temp (or so I thought), mixed the water with the grain, and watched in horror as the mash temp rocketed past the 150 degree F. temp I was shooting for and into the 170+ range. I scrambled to add enough cool water to get back into the 150 degree ballpark and it worked, but man, that is not the way you want your brew day to start. Ugh. I bought a lab grade traditional thermometer the next day, and that’s what I’m sticking with…

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