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BMB Top came off

Hi all,
Still a newbie brewer and trying to get the hang of things.

I brewed a 5 gallon batch of the nut brown ale on Saturday the 4th and noticed on Monday night the top had come off the BMB. I put it back on and its been on since. Do you think the batch is ruined or will it be ok?

It had a small krausen on top Sunday morning when I checked on it, so it started fermenting prior to the lid coming off. It hasn’t had anymore activity on top since I replaced the lid. Do you think this batch a loss? Thoughts?

There is only one sure way to know if the beer is a goner. Check the specific gravity in 10 days and have your first taste.

What is the temperature of the beer in the fermentor? Which yeast did you use?

I should add that some horrible things have happened during a ferment and the beer came out fine.

Those lids need to be weighted or taped down.

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So if it came off, I would suspect that the off gassing may be a probable culprit… With that being said, even with the lid off for a bit, its unlikely anything foreign could compete for sugar to ferment into… ugly stuff! Don’t git mad PC !! Sneezles61

Sneezles!! You’ll wake him up!!

Haha and cheers and +1 to your comment,


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Waiting to know the fate of your beer is frustrating but that’s all you can do. Like you, I learned about the BMB lids the hard way.

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I flip the seal 180° and use a blow off tube until things settle down a bit, then switch to an airlock. Works great!

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Thank you all for the replies. I’ll have to remember to weight the lid down from here on out.

Flars - I’ll be checking the gravity tonight and tasting… Hopefully it’ll be alright.

I’m sure your beer is okay. An infection would most likely be showing visible indications after 16 days in the fermentor.

I use the Plastic BMB for ales…So the inner flat lid just gets blown up off the seal?? Or does the whole ring and Lid lift up???

(I use a standard airlock, occasionally a blow off tube for vigorous fermenters, never had this happen) yet

I haven’t used the BMB for a primary fermentation - just because I’ve read about people’s lids getting blown off. I only use mine for additions in a secondary setting. My personal experience was just realizing that the lid doesn’t seal up without something pushing it down. It was disappointing but the reviews did warn.

I don’t have one but this might be something the manufacturer should be made aware of. Has anyone contacted them or NB? They might come up with a fix. Perhaps they will mail out bricks :wink:


Bricks notwithstanding, a quick fix that I got off this site was to simply use Saran wrap, sanitized in star san, and simply seal the fermenter over a sheet of saran wrap. Poke a hole in it to ease the airlock through the center of the sheet. Works great and brick free. Started out using 2 sheets, but have found that one works just as well.

Again waiting for the OP to answer what in Sam Hill happened to his BMB?

I think Saran wrap should be sanitary right off the roll. Can’t be too careful though.

It is wrong that you should have to go through that with a new fermenter.

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Nice product. I’d ask for my money back.

It has been a known problem should have some mentions in the reviews. I think there are some replacement seals/lids available. EVO-2 was probably the big fix to the problem. I have a BMB. Don’t really plan to use it. Was free with and order. The one I have is the screw on lid/seal type which needs the plastic wrap fix.

What do those things cost ?

Not sure what exactly happened I guess the pressure popped it off, which I thought was weird because I had a blow off tube on it.

As for the brew I plan on tasting and bottling it today if I have time.

I think I paid about $30-40 for it. Disappointed to say the least. Should have just bought the glass carboy.


Perhaps this may help. I tie the blow off tube to a support above the fermentor to relieve the weight and the twist the tube can put on body of the three piece air lock in the carboy bung.

Part of the problem is wet (sanitized) silicone and glass don’t mix. Flip the seal next time so it tapers out instead of in; you may have better luck.

I do this on both my glass and plastic BMB’s.

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