Fermentation temp differences in large vessels

[br1dge]

When fermenting 20-30 gallons or more of wort, I am curious of the temp differential between the "middle" of the wort/beer and the ambient temps of the ferm chamber. Does anyone drive the thermostat off the wort temp, as opposed to chamber temp? Was just looking at optimum temp range for some yeast with narrow optimal temp ranges like 65-68 Degrees and realized it is entirely possible to be way out of optimal range with any measurable degree of temp differential between wort and ambient.

Any references? Couldn't find the right search terms to find anything so far.....

 

[Phunhog]

Well the temperature of the fermenting wort should be the same throughout the fermentation vessel during active fermentation. This should be true regardless of vessel size otherwise pro breweries would install some sort of mixer/stirrer since they are dealing with volumes that often exceed 30bbl or close to 1000 gallons. To the best of my knowledge they don't. I would tape your probe on your fermentor and cover it with bubble wrap. That will help ensure that you are measuring the fermentation temperature and not the ambient temperature.

 

[br1dge]

I agree that all of wort would be consistent, I am referring to the temps outside the vessel vs the temp inside it. Most of us use the temps outside the vessel, and I have heard references of a 5-6 degree difference between inside and outside fermenting vessel.

 

[Phunhog]

You are correct. That is why it is important to either tape the probe to the outside of your fermentor and insulate it. You could also get a thermowell and place it inside your fermentor and place the probe there.