Wednesday 12 May 2021

Is CO2 Gas Leaking or Being Absorbed into Beer?

Pressure fermenting can be tricky - especially when you're first starting out and grappling with some of the different concepts and potential problems along the way.

One of the questions I found I was asking myself during my first pressure fermentation was whether or not I had a leak in my Fermzilla pressure fermenter, or if the gas is being absorbed back into the beer which is causing a reduction in pressure in the fermenter.

Leaks aren't so bad during the actual fermentation - you will need to have a spunding valve attached to your fermenter to help regulate the pressure in the fermenter, so a small leak elsewhere won't actually be noticed until after the fermentation has completed and pressure is no longer being built inside the fermenter by the yeast.

This is what happened to me after my first pressure fermentation - the spunding valve did it's job, and showed the 10psi of pressure it was set to, and any excess was vented out via the spund valve as it should. My problems began after fermentation had completed, and I saw a reduction in pressure to 0 psi overnight. I'd reconnect my gas - re-pressurise the fermenter and leave it again. I couldn't hear any gas leaks, nor could I see any bubbles forming/popping after spraying the entire lid several times with a soapy solution. Sure enough, the next day the pressure would have dropped to 0 psi again.

I continued this process during a cold crash as well and had the same results - and I think I now have the answer to this question based on this experience.

If the pressure is dropping to 0 psi - it's a leak. Plain and simple.

If the pressure is dropping, but not to 0 psi, then it's more than likely being absorbed into the beer. 

Once I discovered the source of my problem (a carbonation cap that needed to be tightened), the Fermzilla would hold pressure and maybe drop a few psi overnight due to co2 being absorbed into the beer.

I wanted to share my experience as I could not find a definitive answer to this problem when I was facing it and found it very overwhelming (and frustrating) trying to understand it.

A pressure gauge reading 0 can be tricky to troubleshoot

What has you experience been with gas leaks and/or  gas being absorbed into your beer? Did you find it confusing the first time as well? Leave a comment below to let me know.


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