Uneven temperatures within fermenting vessel?

[lukins8]

It's the middle of summer here in Australia and I want to regulate my Coopers pale ale at around 18 degrees Celsius (65 Fahrenheit). I was thinking of sitting the bottom third of my fermenting vessel in an ice bath, but was wondering if this would cause temperatures in the bottom of the vessel to be lower than those at the top where fermentation is occurring. What negative effects might this have on my beer? Thanks

 

[jdauria]

You can put in an ice bath and then put a damp old t-shirt over the bucket or carboy, so that the bottom of the shirt wicks the water up and stays wet. Or instead of changing ice all the time, put your beer in a bucket with just a couple inches of water and then add frozen water bottles to chill the water and then just change the water bottles twice a day.

 

[wtfDean]

+1 on the shirt/towel wrap method. I personally just use one of those rope handled plastic utility buckets, insert carboy and fill with water to the level of the liquid in the fermenter. monitor the temperature of the water with a floating thermometer and add ice packs or ice as needed.

 

[fuzzy2133]

No danger of using the bucket/swamp cooler that I am aware of. As yeast ferment the wort it gets all mixed up and moving around. Any cold temperature at the bottom will get mixed/precipitate(?) into the entire batch.

 

[wtfDean]

fuzzy is right, but you'd need to measure the temperature of the fermenting beer to know if you're using enough ice/water to cool the ferment sufficiently. i would get a cheap indoor/outdoor thermometer and tape the "outdoor" probe to the side of the fermenter near the top level of the liquid if you chose to not immerse the entire carboy in water or wrap it with a wet towel. not as precise as a termowell, but you'll be in the ballpark.

 

[petrolSpice]

During active fermentation there is quite a lot of motion and churning going on in the wort. It's clearly visible with a clear fermenter. This motion should relatively quickly distribute the temperatures evenly.

With that said, I put my last batch in a tub with just a few inches of water, maybe 2-3 gallons total. As it got too warm I'd toss in a cold pack. Once it was back to normal temp I'd remove the cold pack. The water in the tub also helps to dampen/slow the temperature swings.

 

[lukins8]

Thanks everyone, I think I will use the wet towel trick as well as the frozen water bottle trick.


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[spaceyaquarius]

No danger of using the bucket/swamp cooler that I am aware of. As yeast ferment the wort it gets all mixed up and moving around. Any cold temperature at the bottom will get mixed/precipitate(?) into the entire batch.

Thermodynamic mixing sure. Precipitation... only if the wort decides to escape the fermentation bucket, vertically travel thousands of feet where it is cooled and then travels back into the fermentation bucket.