View Full Version : How far in should a bung be pushed?

10-24-2012, 10:34 PM
I'm having a hard time finding the right sized bung for my old apple juice jugs. The closest I've come up with are #8 drilled bungs from Northern Brewer...to get them to fit snug they're basically flush with the top of the jug's mouth. This seems a little "iffy" and seems to me that their should be a bit of the bung, say maybe an 1/8 or 1/4 inch, left above the glass edge of the jug.

So, should the bungs be flush? Or, should there be a part of them protruding above the mouth of the jug?


Chevette Girl
10-24-2012, 10:45 PM
Uh, just enough?

Most of mine have at least 1/2" protruding, but as long as it doesn't pop out because it's not in far enough or fall in because it's in too far, you're probably OK.

I have some plastic juice jugs that are a little too big for the bungs I could find so that I've got less than 1/8" above the edge and will go right through if pushed, so I always make sure I only push it in far enough to be sealed and keep the fruit flies out, and not so far it's going to fall into the jug. Oh, and helpful hint I had to learn the hard way, the drilled bung goes in WAY EASIER if you don't have the airlock stuck in it first. Yay for creative use of chopsticks to fish the stupid thing out of my must...

If you're concerned about them falling in, put a cardboard circle or something around your airlock's stem so it won't go any further than that, if I recall correctly a #8's about the same diameter as my three-piece airlocks...

10-25-2012, 05:01 AM
I assume bigger bungs are better, as long as you can fit them in the carboy.
I started out using #12, which left verry little bung on top.

After suspecting leakage i bought some #13, which only go in a
little in the bottle, but this also means I can press the #13 much
tighter than the #12.

Going on the bubbles in my airlocks, its now sealed much better.

10-25-2012, 06:43 AM
Be careful. Fishing a bung out of a carboy is no easy feat. Flush is dangerous, as I have pushed them in, when inserting the airlock.

10-25-2012, 09:02 AM
Thanks for the feedback!

Thankfully I haven't had one get pushed in...yet. Fishing for them doesn't sound very fun. The #8's go pretty much flush with the top edge of the jug's mouth. I feel that I could easily push it into the jug if I'm not careful.

I got some of the "Small Universal Carboy Bung- Drilled #6122" from Midwest that are supposed to be for 3-6.5 gallon carboys...these are even small. I've got a couple of 3-gallon carboys in the shed that I'll try them in but they are definitely too small for the jugs. I'm going to see if I can get a couple of #8.5 or maybe #9 drilled bungs.

Something else I learned is that a wet stopper will creep back out some...works better dry, but then I guess you could be careful and only sanitize just the end of the stopper? Or let them dry in a santized covered dish or... ???

Ah well, they give dimensions for the inside and outside diameters...I think I'll measure my jugs and average those dimensions...get some bungs where the average is equals my jug diameter...should put the bungs down a little over half way in.

We'll see...

Thanks again for the help,

Chevette Girl
10-25-2012, 11:21 AM
I hold my airlock with the bung attached and dip the whole stopper into my sanitizer jar before stuffing it into the carboy. It's possible in your case that the whole stopper is loose enough that it moves with any kind of pressure from fermentation when lubricated with your sanitizer, but I'd sanitize anyway, anything that touches your must or the inside surface of your carboy. If you keep an eye on it for a day or two the excess moisture will either evaporate or drip into the must and you can just reposition it.

Most of my 3 gal carboys will only take a #6 bung, anything bigger would work itself out and I'd find it on the floor in the morning!

10-25-2012, 02:29 PM
After reading this thread, I have decided that I need to warn you all to have a "safe word" decided upon before you initiate the activities mentioned. ;)

Chevette Girl
10-25-2012, 02:42 PM
Smarta$$... ;D