Need Help – Mystery Infection

[Brew Engineer]

Tip 1: Replace ALL your soft lines. Pre-boil, post-boil, kegerator, everything at the same time. While chances are good it's not coming from the lines on your system, you should still replace them annually. Don't let the new ones touch anything until you've cleaned everything out.

Tip 2: If you had a back up into the CO2 system, I'm assuming your gas manifold has check valves (if not, that's likely the culprit - get a new one), so your regulator should be fine. But the manifold/check valves won't be. Disassemble, loose 2 pieces, cuss a few times, find the pieces, boil it, loose the same 2 pieces, cuss once more, find the pieces, reassemble. (You can cut a couple of those steps out, but just trying to be realistic)

Tip 3: When you rebuilt the serving kegs, did you replace the poppets? If not, rebuild them over again. Use a diptube brush on both tubes & a faucet brush on the posts before you put the new rings on.

Tip 4: The keg connectors. Nuff said.

Tip 5: Try a different fermentor. Since you can't see inside there (or at least not very well if you're using a corny), it's possible there's something in there.

Hopefully there's a few ideas in there that might help you out. When in doubt, disassemble & clean it really really well.

I've tried all of those, except my CO2 system. I just thrw out and replaced all my ball lock connectors. I guess I'll have to disassemble the manifold and regulator/check valve and replace all lines.

Ugh

[Ozwald]

That sucks.

I've still been thinking about it down in the shop, but I'm not coming up with any 'AHA!' moments.

Just because it's happening in the kegerator doesn't mean that's the cause, but since it's happening so quickly my suspicions are still there. How old is the gas manifold, and are you sure it has check valves built into it? That would be my biggest suspect & it could mean you don't have an infection in the system. It's just like hooking up a keg of root beer & within a couple days all your beers smell/taste like root beer. In this case it's just the contaminated gas getting passed from a single infected batch (the first one a year ago) to each new keg you put in there & even after that one's gone it'll persist from the ones it infected. Maybe your kegerator just has the clap.

My other, but less likely, thought was how long has it been since you unplugged, scrubbed & sanitized the interior surfaces of the kegerator?

[hoodie]

Are you using pbw? Are you rinsing it out really well? That or the beer lines. I know you said you replaced them, but did you replace them with new lines? I had the same problem awhile ago, it drove me crazy. Almost quit brewing. This is what worked for me.

I meant PBW on the kegs themselves as well as the lines.
The flavor I experienced was slightly acidic, astringent, metallic, hard to describe, but in the background of all my beers. Sometimes more pronounced. I stopped using PBW on my kegs, started hand washing and rinsing really well, even sanitizer. I also replaced my lines and the off-flavor went away. IF you really want to narrow down the problem, you'll need to bottle one or a couple of beers from a batch to see if the problem is in the front end or back end of your process.

[adamK]

This may be a stupid suggestion/response, but have you double checked the co2 pressure? I recently had a slight metallic/acidic flavor from putting the beer at too high pressure, causing a distinctive carbonic acid bite. This was especially apparent for english styles. I backed down the co2, and all was repaired. I was pushing the beer at 12-14psi instead of 6-8. Now it just takes a few days longer to carbonate.

[Effingbeer]

I would have started at the keggerator. Sounds like you know how to sanitize well enough. After replacing all the lines including CO2 lines, if you think it could be a regulator or your manifold, you could bubble your gas through some starter wort and see if it grows something. If it has a high enough bio load to infect a fermented beer, then you should see/smell/taste significant growth within 48 hours or so. If it is clean, it will take maybe a week before you see mold or wild yeast taking hold.
Maybe not bubble through. Turn the gas up kinda high and just shoot it down toward the starter so it doesn't foam up from all the bubbles.

[Ozwald]

bottle one or a couple of beers from a batch to see if the problem is in the front end or back end of your process.

That's a most excellent suggestion. I'd even go so far as to bottle at least a 6 or 12 pack worth to eliminate the possibility of getting a bottle that wasn't cleaned quite enough & thinking that it was the whole batch.

[maxwell]

Where do you buy gas? Are you sure that it's completely free of benzene and other impurities? Occasionally the CO2 sold by welding shops is not pure enough for beverage applications.

[Effingbeer]

Where do you buy gas? Are you sure that it's completely free of benzene and other impurities? Occasionally the CO2 sold by welding shops is not pure enough for beverage applications.

Benzene would suck.