Rubber bung won't stay put

[Budding Vintner]

I just made a 6 gal batch. I racked half of it into a 3 gal carboy for bulk aging, and bottled the rest. Just as I have in the past, I use a rubber bung and airlock in the carboy. For some reason, the bung keeps working its way out of the neck and won't stay tight. I've made sure both the bung and the inside of the carboy neck are perfectly dry, but still the bung won't stay tight. It doesn't fall out, but won't stay tight no matter how hard I push it in. I didn't have this problem at all in my previous batch. Is it a problem for bulk aging if it isn't super tight? I also have one of these I can use - https://www.northernbrewer.com/products/3-5-6-gall-carboy-cap-orange - that would stay secure, but I don't know if it will be airtight enough. Any advice from you experienced guys?

 

[ChuckD]

I have that problem occasionally. Less often with silicone bungs. When I do I just cram it in there and use electrical tape to hold it in place.

 

[sour_grapes]

I use the universal-style bungs. For me, they start out as you describe, so I proceed like @ChuckD recommends. Eventually, they "take a set" to the compressed position, and stop working their way out.

 

[Ohio Bob]

Two ideas...
I’ve had them work their way out. Sometimes changing the size 1 step helps. Instead of a 6.5, try a 7, or maybe a 6.

Secondly, I use Everclear in my airlocks. I also have a plastic 50ml beaker, really a cup, which I fill with about 1/8” of Everclear. I dip the airlock/stopper in the Everclear before inserting it into the carboy. It usually will stay exactly where I put it. Next step is to pour the beaker into the airlock, any excess goes back in the bottle. I earmark one bottle just for these purposes. Not to be mixed in with the wines or ports.

 

[Rocky]

I have found that roughing up the surface of the stopper with sand paper works for me. It seems to hold them in place and removes the "glaze" on the stopper. I also use a #6.5 stopper. I cannot get the #7's to stay. If you are a "belt and suspenders" guy, you can also take a 6" length of 2" duct tape, cut a slit in the center to fit the airlock through, tape it down and then wrap more duct tape around the ends at the neck. I have done this but it is a PITA when you have to get into the carboy for any reason.

Also, I would recommend against using the carboy cap if you are looking for something airtight.

 

[Rice_Guy]

All of my five year old stoppers are turning hard and as a result are hard to seat. If it is hard to push a finger nail in the rubber I toss it.
I would use a two hole cap as in your link on wine that is under a year old. If this is what I have today I would use it today. Your risk of oxygen transmission exists on wine over a year old but should be less than having a lose cork.
I have solid corks on many carboys over a year old. The other option I use is a check valve and -22 inches Hg vacuum.

 

[Greg Corey]

I have this problem extensively with 1gal carboys. Pick up some very thin bailing wire or jewelry wire. Do a little wrap around almost like a sparkling wine wire hood. It's a great, reusable way to keep bungs in.

 

[QuiQuog]

I also have that problem nearly every time. There seems to be a difference between dried with a towel and actually dry. I just check it a few times the day I put it in and push it back down, and then into the next day. Eventually it seats and stays.
I've tried using one of those orange caps to route overflow in an especially active ferment. It started leaking foam out between the carboy and cap immediately. I wouldn't trust it for an airtight seal.

 

[Budding Vintner]

Good suggestions, thank you! I decided to use duct tape trick as I had it handy and it seems to be working fine now. I'll save the orange cap for some other use.

Somebody should design a bung that is cylindrical instead of conical in shape, to match the carboy mouth and not try to squeeze itself out.

 

[ChuckD]

Somebody should design a bung that is cylindrical instead of conical in shape, to match the carboy mouth and not try to squeeze itself out.

I think if it were cylindrical you would have the opposite problem. It would be hard to insert and would get stuck.

 

[bstnh1]

I've used use the rubber bungs, both drilled and solid, in 6.5 and 5 gallon PET carboys for over 12 years and have never had one creep up at all. For the Better Bottles I use the universal bung; for the Vintage Shop carboys I use a 10.5 rubber bung.

 

[mainshipfred]

I also have them creep up on me and sometimes blow off but could never figure the rhyme or reason. Air or towel drying could be the reason I just don't know. As a precaution whenever I first install a solid bung I put a baggie over it held in place with a rubber band. It at least doesn't let it blow off. Eventually the bung does stay in place. The recommendation of using a smaller bung also sometimes works.

 

[Mekpdue]

I've used use the rubber bungs

The rubber bungs are much better than those 'terrible' silicone ones. I'm now buying pre-drilled rubber stoppers when i need them exclusively. Wish I never bought those silicone ones. 8 outta 10 times I have to design something to hold them down for a few days. Zip Ties or thin wire seem to be the best solution. Also, some people have tried heavy rubber bands to some success.

 

[Raptor99]

I've had this problem too, especially with one-gallon jugs. It helps if the stopper and the inside of the neck are completely dry. I also discovered that one batch of stoppers that I purchased was a little harder than the others. That one would always creep up. I gradually removed the too-hard stoppers from service, and that helps.

I just check it a few times the day I put it in and push it back down, and then into the next day. Eventually it seats and stays.

That works for me as well. The first few days, I push it down several times per day, until it stays put.

 

[wineview]

I have some difficulty at times with my newer bungs. They are bright white. My older ones never creep out. I believe the material of the bung has changed. The new white ones are a bit stiff whereas the bungs that are 25 years old are a tan color and feel more like rubber. I’ll never give those up. For any bung I usually push it into the carboy with the palm of my hand and then insert the airlock. That seems to address the slipping issue.

 

[BernardSmith]

I wonder if another possible solution to prevent bungs from riding up and out the mouth of a carboy is a) to insert the airlock after you have inserted the bung. IF - IF the airlock to bung fitting is to be air-tight, inserting the airlock after (and not inserting the bung AND airlock as if a single unit) should slightly deform the bung and may help force it against the side of the neck. It's also possible that the lower part of the tube of the airlock is itself either too wide or too narrow and both conditions may affect how the bung sits.

 

[Clover]

I use plastic coated wire and build a kind of cage. I loop the wire once around the airlock and twist it away from the handle, make a few twists down that far side of the carboy neck, then bring each side around the neck toward the handle, pass them through the handle, bring up in a criss-cross and loop around the airlock and bring them towards the handle, pass them through the handle on each side, then twist the ends together to hold in place. Sounds complicated but isn't. Works like a charm and keeps the bung snug, and the plastic coat won't scratch or cut into anything.

 

[wineview]

bring each side around the neck toward the handle, pass them through the handle, bring up in a criss-cross and loop around the airlock and bring them towards the handle, pass them through the handle on each side, then twist the ends together to hold in place.

What handle are you making reference to?

 

[wineview]

The rubber bungs are much better than those 'terrible' silicone ones. I'm now buying pre-drilled rubber stoppers when i need them exclusively. Wish I never bought those silicone ones. 8 outta 10 times I have to design something to hold them down for a few days. Zip Ties or thin wire seem to be the best solution. Also, some people have tried heavy rubber bands to some success.

Where do you buy your rubber bungs?

 

[BigDaveK]

As far as 1 gallon jugs, mine are made by 3 maybe 4 different manufacturers. Very slight differences. I noticed the Made in USA never has stopper creep, one brand is hit or miss, another absolutely hates stoppers and I have to use tape.