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Big mouth bubbler?

So it is my first time using my 6.5 gallon plastic big mouth bubbler. I love it so far, especially putting everything in it, but after the first 12 hours my blow off tube stopped bubbling. I replaced it with a air lock and nothing either. The thing is, I’m still seeing plenty of fermentation activity. So I’m wondering if there is a leak? It would have to be small. I think I saw others saying they’ve had this issue with theirs, but I just want to make sure it isn’t a big problem.

Thanks! :cheers:

Buckets often act this way. I bet you’re fine.

Since there isn’t any kind of gasket on the lid, the possibility of a small leak is there. Check to make sure that the rim of the bubbler is perfectly smooth, and you could use a little food grade lubricant there to help the seal. A leak that small shouldn’t cause you any trouble, though.

I understand your concern. Some of us just find enormous comfort in watching those little bubbles move through the airlock!



I was thinking of these just yesterday as I was trying the clean the dried crud from inside my carboy by swirling a washcloth inside. It sure would be nice to just reach in by hand.

Actually, there is a very thin gasket in the lid. I bought a 5-pack of replacement gaskets along with my bubbler. Mine has held pressure for about two weeks now - racking to the keg this week.

I didn’t find a gasket with mine–that would be nice. Mine has held pressure even without one, though. I just have to screw the lid down very tightly.

Gonna get some of those gaskets. Thanks, Capitan.



The glass BMB’s come with a lid gasket. Plastic versions do not. On the plastic version, the white lid has an outer groove so that it sits inside the opening of the container. A gasket would not help that seal. Just make sure the lid is seated properly and tighten the ring.

I have noticed that the ring will loosen slightly as the plastic BMB cools down. If I fill it with 70 deg wort, then put it in my fermentation fridge at 62 deg, I’ll have to re-tighten the ring in a couple hours.

Yeah Mine’s the plastic one. So no gasket. I do like it, though.



Mine doesn’t do this, but if it did I’d use a bit of keg lube on the white lid and plastic wrap around the blue ring after sealing.

I just cleaned up my 6.5 gallon glass BMB for the first time, and it was a breeze. I think I cleaned it more thoroughly than I really needed to, just because I could. Yay! I’ve been fermenting in buckets for a few years, and I’m happy to be back to glass for now.

I sewed my own harness, adding a few improvements over the commercial version - namely a padded bottom. It was pretty easy to do and cost me a total of about $8. And sewing is another hobby of mine, so the time spent was fun.

:cheers: to DIY

I’ve got the glass version and had a similar issue. I now use two of the gaskets together and have not had an issue since.

Been through 2 of Big Mouth plastic fermenter’s, neither of them had any air lock activity, of course you can see the active fermentation, but I do not like the fact that there is some kind of leak. 3 batches through them came out fine. Have gone back to the “old” style plastic 6 gallon and all is well with air lock activity. I think the big mouth is a poor product.

Agree with sailfast. Leaky lidded plastic junk I’d expect to find in Walmart not Northern Brewer. Back to glass I guess. Can’t afford to chance it.

Just bought the 6.5 glass model. Appreciate the Q&A here.

What’s the deal with the bubbler that’s built into the lid? It looks like you can screw it on in such a way as to leave a larger opening for blowoff and tighten it down after things settle down. Is that correct? Does anybody use the bubbler in the lid; or do you get a separate stopper, bubbler and blowoff hose?

PS - I had thoughts of swapping it for plastic, but will stick with glass thx to comments here.

PPS - Did you see the youtube of a guy whose glass BMB shattered due to a thin spot? He showed it next to an egg shell and it looked about the same thickness. The product description even says that it “…is a large hand-formed glass item that can be easily damaged if not used with proper care and handling. It may have variations in shape and thickness…” So be careful!!

I’ve got both the plastic and the glass Big Mouth Bubblers. I can say unequivocally that I prefer the plastic. Here’s why:

–I had to get eight stitches on my left thumb because I broke a glass carboy while cleaning it. Now any time I use the glass bubblers outside on my concrete patio I’m convinced I’ll shatter one just putting it down. That’s just not a concern with the plastic.

–The plastic bubbler is lighter. It’s not a huge difference, but it’s noticeable.

–Like many people, I had a leaky lid at first. I solved that problem with a thin smear of keg lube around the outside of the plastic lid. It was such an easy fix that I genuinely don’t understand why people complain about the lid.

–The port on the top of the glass bubbler is undersized and can’t accommodate a thief for taking gravity samples. I also like the double-port option for the plastic bubbler. I don’t presently do this, but I like the idea of using gas to push the beer into a flushed keg someday.

–I like that the plastic bubbler is taller and skinnier than the glass one. I can fit the plastic bubbler in my fridge next to my kegs when I brew lagers, which I can’t do with glass.

–I’ve never had any sort of infection or other contamination problems using the plastic.

What exactly are you worried about?

I have the 5-gal plastic now. I’m using it as a primary for 3-gal batches. My first batch’s krausen is almost fallen, and never any sign of increased pressure on the 3-piece airlock.

I think it’s sealed enough to prevent infection so I see no need to worry. I might consider a thin bead of silicon on the top of the ring, and perhaps Teflon tape on the neck for longer fermentations. But I see it as piece of mind more than actual need.

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