BrewBuilt™ Neoprene Carboy Sleeve

BrewBuilt™ Neoprene Carboy Sleeve

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Have you been struggling with fermentation temperature swings? The BrewBuilt Neoprene Carboy Sleeve works great for maintaining the internal temperature of your 5, 6, or 6.5 gallon glass carboy. If you aren't fermenting in a temperature-controlled environment your beer is likely rising and falling with the ambient temperature, and these swings can stress out yeast and have a negative effect on the finished product. This 6 mm thick neoprene sleeve will help retain the heat naturally produced by fermentation activity and provide some protection from the ambient environment, leading to more consistent fermentation temps, happier yeast, and less off flavors in your beer.

We highly recommend the neoprene sleeve for use with the BrewBuilt Carboy CoolStix. The added insulation will lower the amount of cycles needed to maintain fermentation temperatures and is a must-have for cold crashing.


SKU Size Height (in.) Diameter (in.)
FE329A 5 Gal 14.75 10.75
FE329B 6 Gal 17.25 10.90
FE329C 6.5 Gal 17.50 11.20


Community Q&A

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Inefficient carboy chilling
Joseph T on Sep 26, 2020
Inefficient carboy chilling
Joseph T on Sep 26, 2020
Need insulation for my ferm temp control system
Michael Murdy on Aug 13, 2020
Need insulation for my ferm temp control system
Michael Murdy on Aug 13, 2020
Does this fit the 7 Gallon Fermonster?
Colten Zachary on Apr 28, 2020
BEST ANSWER: The size you will want for the 7 gallon fermonster is the FE329C made for the 6.5 gallon glass carboy. The Fermonster is 11.3" diameter and the jacket will stretch that last 0.1" to snuggly fit the fermonster.
Is there any reason this wouldn't work as kettle insulation for a 5-6 gallon kettle (Like the SS Brewtech)? I do electric BIAB and the dimensions are almost perfect for that application. With an induction cooktop I doubt the kettle would get hot enough to melt the neoprene. Thoughts?
Tysen Bibb on Apr 17, 2020
BEST ANSWER: This should work fine for that application since you are using an electric heater. Neoprene seems to have a burn/melting point over 250 degrees fahrenheit so it should be safe. That said I do recommend watching it diligently for the first few brews and you should always have a good fire extinguisher at hand any time you are brewing with any system just in case.

4.7 / 5.0
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Pretty good insulator
Together with a stainless insert, the sleeve allows me to reach an external temperature in a carboy onky about 6° higher than my lagering chamber. Nice.
September 1, 2020
5 months ago
I works great with a 6.5 gallon Big Mouth Bubbler.
June 7, 2020
8 months ago
Carboy Sleeve
Great fit and seems durable!
April 22, 2020
9 months ago