Did I funk my other kegs with CO2?

[pint33]

So I have a four tap kegerator with only one regulator on an external CO2 tank. The one line from the regulator is shared - it splits four ways, evenly, inside the kegerator, across all four kegs.

This week I put a new brett (funky) saison on one tap, and a new normal clean IPA on another tap. The other two lines have a clean pilsner and a clean Duvel clone that have been pouring (and tasting) fine.

I needed to force carbonate the two new kegs, so I turned the CO2 up to 20PSI for two days and then turned it back down to 11 PSI for serving. Carbonation is good for the new kegs. But for some reason I thought it would be a good idea to bleed/purge the CO2 lines when reducing the CO2 pressure, and that’s what I did - I opened the pressure release valve on the regulator (not the kegs), zeroed out the gas pressure from 20PSI to zero, turned the pressure back up to 11 PSI, and poured a beer from each of the new kegs. The new kegs have good carbonation and pour well.

However my stupid paranoid brain said, “Did you just bring brett funk “fumes” back into the split CO2 line while depressurizing?” Really? I mean is that possible… meaning, when the depressurized rush of gas flowed BACK into the valve I opened on the regulator, could brett “fumes” have somehow made their way into the shared gas lines, sat there for a moment, and then when I resumed the normal CO2 flow could any brett fumes get pushed into the other kegs thus infecting them? There was no indication that any beer had been sucked back up into the gas lines while I was depressurizing.

I’m only 24 hours in. My homebrew shop said to wait and see what happens and to taste the kegs in a month or two to see if the other kegs have become funked.

I read somewhere that microbes/bacteria (like brett) can’t live in a CO2 rich environment and also cannot survive a “flight” to another area.

So maybe the brett keg did not really have a chance to release brett back up into the line at all? No beer went back up into the line.

Any advice is appreciated!

 

[Broken Crow]

You're probably OK if it's just fumes... The part you need to watch out for is if the beer itself or even foaming from rapid pressure changes shoots up the gas line. Did you see any beer or foam in the lines?
Just a trick I use for 'venting' pressure from a keg in my kegerator: I connect the liquid line and pour some.... usually 1/2 to a pint will drop the pressure by +/- 10psi. I've currently got 4 kegs on one line too and I make it a rule to never pull the PRV on either the regulator or any keg while the gas is plugged in....I fear the backwash!

 

[pint33]

Thanks and yeah I’m thinking it should be ok too. The gas lines looked dry, which is surprising. I guess I’ll know in a month or two. Note to self - don’t put wild ale on tap next to clean beer.

 

[PCABrewing]

You might consider check valves on each line at the splitter.
While they wont guarantee no back-flow they'll help.
They may also help in the case you run out of gas and don't notice it for a day or two.

Bacteria can spread on a suitable surface regardless of air movement so even if gas doesn't back-flow, the colony may creep along the interior surface of your lines as the cells divide and the colony expands.
This is bad enough, but if you are unfortunate enough to develop a biofilm it will make subsequent eradication pretty tough. Crevices (threads, check-balls and joints) make it worse.

 

[JohnDBrewer]

Let us know if you notice the cross contamination.

 

[suprchunk]

Just buy new poppets, and seals. Switch them out and never let them mix.

I've had a few infections from o-rings...ymmv.