Double Batch. 2 Carboys. Different temps?

[carolinabeerguy]

Strange question/issue: I brewed a 10 gallon batch today. I used my copper immersion chiller to cool it down and relied on the thermometer in my SS Brewtech Brewmaster kettle to assume it had gotten down to my preferred 68 degrees. I proceeded to drain the kettle into 2 carboys and pitched my yeast as normal.


Here’s where it gets weird. I just happened to look in on them and noticed that one carboy was sucking back some starsan through the blowoff tube. I switched to a airlock, but noticed that the carboy felt warmer than the other. I used an infrared thermometer and verified that the other one was 70 degrees while this one was 92!


Could this be caused by an inaccurate thermometer? The only thing I can think is that the second carboy was filled with a good amount of wort from below the thermometer. I typically use a ThermaPen, but I had to send it back for repair. I moved the carboy to my freezing garage and hope I don’t have to dump half my batch. Thoughts/suggestions?


TL;DR: Brewed a double batch and somehow 1 carboy ended up 20+ degrees warmer than the other.

 

[jekeane]

are you stirring or whirl pooling your wort? If not it is likely a result of temperature stratification. Wort is a very good insulator so if you are not moving it around your chiller you are going to get stratification.

your wort chiller may have been touching your thermometer as well which could give you a false reading.

It is certainly possible you need to calibrate you kettle thermometer but I would tend to think it was more of a not enough stirring issue.

 

[carolinabeerguy]

are you stirring or whirl pooling your wort? If not it is likely a result of temperature stratification. Wort is a very good insulator so if you are not moving it around your chiller you are going to get stratification.

your wort chiller may have been touching your thermometer as well which could give you a false reading.

It is certainly possible you need to calibrate you kettle thermometer but I would tend to think it was more of a not enough stirring issue.

Yep, that’s the issue. New kettle and didn’t whirlpool. I always whirlpool my hoppy beers, but never thought about it with a light oatmeal stout. Good call!

 

[wilserbrewer]

Fwiw, I think you should stir well before taking any temp, be it strike, mash, post boil, perhaps not during the boil lol but any other time for sure.

 

[carolinabeerguy]

Fermentation is happening in both carboys so I may be good after all. We shall see.