Sale & Clearance
Deal Of The Day
Carboy Bung (Silicone) - Breathable
In Stock
Delivers to ( change ) by as part of our Fast & Free Shipping.
Faster Shipping Available. Details.
60 day no hassle return policy. Details

This high quality Silicone Stopper gives a great airtight seal while still allowing gasses to escape. 
Fits 3,5,6 & 6.5 Gallon glass carboys and 500ml flasks. This breathable Silicone Carboy Stopper acts as both a solid stopper and an airlock. The unique design allows CO2 pressure to escape but keeps oxygen and airborne contamination out. Beer makers love using it during the ferment because it creates a vacuum when the wort cools, instead of pulling water in from your traditional airlock. The airtight seal is great for extended lager fermentations when CO2 production is still present but only very slightly. 
Measures 1 1/2" wide at the top and 1 1/8" at the bottom.
You may also want to check out our Premium Breathable Silicone Carboy Hood.
Item # FE479
Shipping Eligible for Free Shipping Program
Availability California - In Stock
Pennsylvania - In Stock
Weight 0.10LBS
Community Q&A

Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 1 question Browse 1 question and 2 answers
Why did you choose this?
MoreFlavor Store
Have one and love it. I use plastic carboys which can suck in water from a regular airlock when flexed when moving.
Karyl N on Jan 25, 2018
Have one and love it. I use plastic carboys which can suck in water from a regular airlock when flexed when moving.
Karyl N on Jan 25, 2018
I want to fill holes in things
I want to fill holes in things

4.9 / 5.0
8 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
Great when stacking carboy carriers 3 high and 3 deep...
January 27, 2018
1 month ago
great alternative to a typical airlock
These are a great alternative. No need to fill--or top up--with water. They also prevent any backflow of air (such as when cold stabilizing). One caution: when wet they are quite slippery and can pop up. It helps to give them a twist as you're inserting them.
January 24, 2018
1 month ago
Nothing Better
I have been making wine for 15 years and was in a continual search for "the" best stopper available always coming up short in one area or another. That is until now. When they first became available I bought two for a trial run, impressed I bought four more. Finally, I got fed up with messing with the bubblers and bought 10 more. If you are serious about your wine making procedures then you must own these. There is nothing better in market place than the silicone breathable stopper.
Two important features you will be impressed with -- 1. they don't need water to work 2. They don't extend the height profile of your carboy by six or more inches.
July 4, 2016
Best Carboy Stopper Yet
I have tried many stoppers and no matter how dry the stopper or carboy neck, they don't fit well. This works like a charm! Push down the top and it seals tightly When you open it you can actually hear the vacuum break.
October 21, 2015
A better way to go
I've use these for beer and wine making for three years. I don't see any reason to revert back to the bubblers.
August 7, 2015
Simple device-excellent results.
These are very high quality. I have these on all my carboys. good positive seal. I am buying more.
May 3, 2015
Silicone Stopper (Breathable) replacing Bubblers
I have always had problems with "Bubblers" drying out or pulling the liquid back into the wort. These have totally solved this issue. If your recipe has a very active yeast and has an issue with bubble over; just keep an eye on it, and clean with Pipe cleaners as needed.

Not all "Silicone Stoppers" I found on-line looked the same. These have a top cap the allows vapor out. These allow the brewer to check active fermenting pressure with a touch of the hand.

I will buy more of these.
December 1, 2014
Strap it on
I use this to ferment lagers, as the freezer I use is not tall enough to accommodate an airlocked carboy. Even when the opening and stopper are dry, off gassing from fermentation will push the stopper out before the vent opens. I just rigged up some wire ties to hold the stopper down during fermentation to solve the issue. The carboy does build up some pressure, and I'm not sure how this affects the yeast, but I'm sure it's no more stressful than the pressures of working in a 50 barrel fermenter on a commercial scale. This works great for my purpose, but the wire ties might be too much trouble for some brewers.
October 28, 2013