airlock won't stay in carboy

I can't believe I am the only one with this problem. My stout was bubbling along just fine with a blowoff tube for a couple of days. I then checked it last night and the stopper is out...I don't know for how long. I messed with it for a while and finally think I have it fixed but this morning I had the same problem. I switched to a standard airlock, but having the same issues. It just slips out.

Any ideas for keeping it sealed but still able to remove it once the fermentation is complete?

Hopefully I did not get any contamination as this was a relatively expensive brew.

I have a few weird rubber stoppers that tend to pop back up out of a couple of my more narrow-necked carboys. I try to use my red rubber carboy caps with those carboys, the ones that cover the neck completely. If I don't have a carboy cap available, I'll secure the stopper with a few wraps of electrical tape.

I doubt you had any contamination as the stout was emitting lots of CO2 before you discovered that the stopper was out.

My glass carboy does that too if the rubber stopper or the neck of the carboy is wet. I just wipe it dry and it stays in place

My last batch i also had this issue, i have a carboy handle which made a convenient point to anchor a piece of twine to tie the stopper down.

kfz said:

My glass carboy does that too if the rubber stopper or the neck of the carboy is wet. I just wipe it dry and it stays in place

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Same here. I just wipe them dry also.
I did have a problem with one that still wouldn't stay in so I just used a couple pieces of tape to secure it.

When I first put the stopper into my carboy, I dry the carboy neck (below the very top) and place a layer of duct tape around that, and then put strips of duct tape over the stopper secured to the ring of tape. That ensures it stays on. Tends only to be a problem for me at the beginning of fermentation when things are most vigorous, though.

This is why I love carboy caps that completely cover the neck of the carboy. So much easier to get on/off and no slippage from being wet.

Are the carboy caps air tight? I seem to recall seeing something about them not being air tight like the stoppers. Also, will they stay on during extreme fermentation such as with a Bavarian weizen? I have never been truly happy with the standard stoppers so I am ready to try something different.

bierandbikes said:

Are the carboy caps air tight? I seem to recall seeing something about them not being air tight like the stoppers. Also, will they stay on during extreme fermentation such as with a Bavarian weizen? I have never been truly happy with the standard stoppers so I am ready to try something different.

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I never liked the fit of the orange carboy caps, but these red rubber ones fit air tight and don't slip when wet. I get hearty blowoff through mine without them coming off (like this).

same issue on my 3 gallon carboy. Take some aluminum foil (the width of the stopper) and wrap it around the stopper. It stopped mine from popping out

Try rubbing your stoppers with some alcohol.


Worked every time when I was still using carboys.

Update: Although I knew better, I still had concerns about the final product after at least two 12 hour periods of an un-capped carboy (possibly longer). I bottled it a little less than two weeks ago. I, of course, tasted the uncarbonated beer and . . . amazing. It was clear with a perfect balance of flavors. Now I am waiting for the bottles to carb up for the next test.

So, the moral of the story; don't stress about little things like the stopper blowing out of your carboy. I still think I will try a different cap as I plan to brew a weizen next, and we all know how that goes.

E-Mursed said:

Try rubbing your stoppers with some alcohol.


Worked every time when I was still using carboys.

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+1!! A little rubbing alcohol (isopropyl) on a paper towel and give it a quick wipe. The bonus is the typical rubbing alcohol is 70% and is VERY effective at killing microbes

Make sure everything is dry and stick it further into the bung next time

Orange caps rock. Starting like 10 yrs ago, the orange caps suddenly got rather thin and skimpy, but yet of the 7 or 8 I've owned over 20 yrs, I've only had one that didn't seal quite airtight (a zip tie solved that). I'll never use anything else.

It's common with starsan users.

If you're using Iodophor the stoppers will stick even when wet, there is no surfactant in it.

if you're using starsan you have to wipe your bunghole.
https://www.homebrewtalk.com/f14/wiping-my-bunghole-402581/

also some carboys like #7s some like #6.5s

amandabab said:

if you're using starsan you have to wipe your bunghole.

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Oh boy, this could easily go down the wrong path now....

BostonianBrewer said:

Make sure everything is dry and stick it further into the bung next time

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That's...not what she said.

A couple strips of Gorilla tape worked for me, albeit slightly overkill.

Life could be worse......first batch (circa 1993)....I pushed the stopper into the carboy. I can't remember how I got it out, but age will do that to ya.