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Pushing beer out of fermenter with CO2

Hi gang.
I’d like to push out fermented beer our of my Big Mouth Bubbler fermenter, with CO2. I seem to recall an accessory with a double drilled lid, but my question is: how do I go about ensuring that I don’t pump in too many PSI and explode the crap out of the walls of the fermenter??


Very simple… Turn the regulator down… zero… zilch… Then once you’re all hooked up start moving the pressure up… What few I did, I got about 3 PSI and the cap was leaking… I thought a hose clamp could’ve help immensely… Still it did work! You’ll need to experiment… Even if its with water just to get the bugs worked out before its for real. Sneezles61

Don’t worry about exploding the BMB. I just tried to do exactly what you said and didn’t have good luck… I turned the pressure down to 1 PSI and still couldn’t get the beer to move out of the spigot. The lid immediately popped off when I turned the gas on. I’m gonna try a couple ratchet straps over the lid and then turning the pressure on. By the way, I’m talking about doing this on my plastic Big Mouth Bubbler with spigot.

Here’s a discussion with a picture. We use duct tape or our hands to hold the lids on to get started. Start with zero pressure and slowly increase watching for the beer to rise in the siphon tube. Once the siphon starts, with a little finesse you can balance the CO2 pressure so you don’t need to hold the lid on since the siphon tries to pull a vacuum.

Transfer to keg under CO2 pressure

Ah geez, I didn’t read ALL the words/letters… I’ve never messed with a big mouth bubbler… Sneezles61

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One way we monitored pressure was to gently press on the side of the fermenter before we put any gas to it to get a feel for how stiff the walls are. Once we start the flow we do the same thing every now and then just to make sure it’s not getting too much pressure. I also think that the stopper should blow out before the vessel goes since that’s happened during fermentation.

Use a bucket fermenter.

Your thread back in January is what inspired me to do this @WMNoob! Maybe I put the liquid disconnect on the “IN” side of the keg or something silly like that. I know I had the PRV open… why did you drill a second hole for a second stopper? I just put my racking cane through the same hole that my airlock was in. Maybe that’s what i need to do different?

Out fermenters don’t have spigots so we need gas in and liquid out in the lid. Our whole setup is: gas into the fermenter through a small piece of racking cane above the beer, a long racking cane out with a liquid out connection hooked to the keg’s liquid out post, a gas in connection hooked to the keg’s gas in post for a vent with plastic tube in some StarSan. It’s nice to have the vent tube in something so you can keep an eye on rate using the bubbles.


Thanks all! And, nice pics

Looks pretty straight forward

Thank you for the pictures and explanation. I wrongfully assumed that your BMB had a spigot (like mine) so thats why I was confused as to why you had two holes in the lid. One more question… why not just pull and twist the PRV a quarter-turn to vent the keg?

Simply because I’m a freak that way. LOL That would work for sure but I like judging the flow from the bubbles and if I have a little more than a kegful then i catch the overflow. No other real reasons. :sunglasses:

Gotcha man. I did a test run of the whole process again the other day… this time with Star San and not beer, and it went great. Thanks again for the help.

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Glad to share and be sure to let us know if you happen on to any tricks for the process. Cheers!

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