controlling temp during fermentation

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RobDrechsler
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controlling temp during fermentation

Post by RobDrechsler »

In reading byo, which was talking about using a temp controller with a fermentation chamber. it was talking about the difference in temp between the side of the fermentation vessel vs the middle of the wort. So the question is , could you use a large type stir plate during fermentation to even out the temperature throughout the wort? Then turning it off as fermentation subsides to allow flocculation?
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Bill Lawrence
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Re: controlling temp during fermentation

Post by Bill Lawrence »

I suppose you could but frankly I think that is overkill, there are other things you could be paying attention to that would likely improve your beer more than doing that. Incidentally, although I read BYO frequently, you really should take the stuff you see in there with a grain of salt. There was a big article concerning hops in the last issue however they did not even bother to discuss the effect of low cohumolone hops on bitterness and flavor. I also saw a discussion concerning "dryness" and mash temperature where they implied that a beer's "dryness" was related to mash tempature. Sure, if you have alot of dextrins in your beer the final gravity will be higher but dextrins have no flavor so the beer will not necessarily taste sweet, that is mosty a function of the yeast and O.G.. Also, there are frequently many errors in the text, especially the numbers. Whoever proof reads the articles is likely not a brewer so issues like that frequently get missed, either that or they do alot of taste testing while proofing the articles (likely a occupational hazard). The articles are however fun to read and I sometimes get some good ideas looking at that magazine. :D
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Jimmy Orkin
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Re: controlling temp during fermentation

Post by Jimmy Orkin »

I heard Jamil say that the temperature on the side of the carboy is the same as the temperature of the beer in the carboy. During active fermentation the beer movement. Look at the yeast moving around.

I attached my temperature sensors to the outside of the carboy.

That said I want to do some experiments to prove or disprove Jamil's statement. I have never gotten around to it.
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Guerra
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Re: controlling temp during fermentation

Post by Guerra »

jimmyorkin wrote:That said I want to do some experiments to prove or disprove Jamil's statement.
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NanoBrew
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Re: controlling temp during fermentation

Post by NanoBrew »

I agree that within the fermentation that the temperature difference is negligable between the center and the outside (I have done some testing myself).

However.... The fermentation chamber that I use is the large beverage cooler type with fans that circulate the air inside the cooler accross the evaporator coils. I had originally started out attaching the thermocouple from my temp controller to the side of the fermenters and noticed that in warmer weather the controller was cycling every ten minutes. The controller was set for a 3 degree differential, so knowing that the temperature of the wort could not possibly increase that fast with ambient temperature inside the cooler I deduced that it was the air circulating inside the cooler when the compressor was not running that was influencing the temperature measurement. (the fan motors themselves create heat) To solve the problem I placed the Thermocouple inside a thermowell directly down the center of the fermenter. Problem solved! It now only cycles a couple of times an hour.

The point to all of this is that while the temperature difference is not significant from the center of the fermenter to the outside, your temperature measurement can be greatly influenced by outside sources.
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