Introduction: Make a Growler Pressure Cap

Picture of Make a Growler Pressure Cap

I'm a craft beer lover and started gaining weight. In order to be able to enjoy my passion I had to change my diet and I'm now all Paleo... all the time. In order to enjoy an entire growler of fresh ale I must pace myself. Thus I have to keep a growler's contents alive as long as possible. Thus I made growler cap, similar to the ones I use on PET bottles with a gas/CO2 fitting is a necessity.
Please note: With no pressure relief valve, you must NOT overfill a glass growler.  I always set my gas below 10psi and I would recommend you wrap the growler in a thick towel when adding pressure.  

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DonavanK (author)2015-10-13

Took me a bit to find. Search for parts:

Grolsch EZ Gasket

tr416 valve

thespeas (author)2014-11-04

Nice! I was about to start this project, but found this pre made contraption.


kirkb150 (author)thespeas2015-04-24

I'm to cheap to buy that. Nice idea though.

RobertS36 made it! (author)2015-04-20

You can get a 3-PACK of growler preservation caps for pocket change on Amazon ( All you need is a CO₂ dispenser. Sounds like kirkb150's pressure regulator, a co2 source and a common air blower would do the trick. Follow his advice and take care with your pressure settings. I've tested glass growler. They seem to break under hydrostatic pressure testing at above 100PSI. Obviously, you don't need high pressure. But just 2 let U-know that - FYI. If you wish to test your growler to 60PSI w/o risk, fill it with cold soda, pouring carefully so it does not foam up and lose carbonation. Fill it to the rim and cap it. Set it outside or somewhere it will warm up to 75-80 degrees F. The beverage industry standard level of carbonation for CSD's is 60PSI. It's very unlikely that your growler will crack at that pressure. If your growler passes the test, then you'll feel quite safe working with beer pressures.

kirkb150 (author)RobertS362015-04-24

I use beverage gas so I know it won't have anything toxic or that will effect the flavor of the beer.

Oh those rubber gaskets are available at homebrew supply stores and online. They're replacements for fliptop bottles.

kirkb150 (author)2015-04-24

I made these because the carb caps were expensive at the time. Certainly interesting in new solutions, but I'll let a few others (early adopter types) find the flaws, if there are any.

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