Vinegary smell...

[Rowang]

Alright guys,

Just cracked into a pint from the barrel after a week off the booze... as i knew it would, the world has fallen apart without drinking. Not quite that bad, but my beer has a slight vinegary smell to it, even though it can only be a month or so old, and is 5% ish.. I checked the pressure on the barrel by releasing it and recharging with a cylinder, and the pressure had help well, really well! I also made sure I burped all the gas out of the keg when i first kegged up, so what would be causing this? and how quickly is it going to spoil?? At the moment, its at the point of "smells a bit...but I cant be arsed to take it back to the bar.."

Any ideas?

Cheers

[gnorwebthgimi]

Could be acetobacter, causes vinegar tastes because it's the bacteria that makes ethanol into acetic acid (vinegar).

You could campden it to kill the infection, or just leave it and hope it doesn't get worse or gets better (unlikely).

At any point did air get into the barrel before carbonation kicked off?

[Rowang]

Im a bit wary of introducing more O2 than necessary, i think that will cause more adverse effects than the potential gains.
Also, its been sat in there a month or so, if it was infected wouldnt it have been expected to have been vinegaryer quicker?

Its drinkable now, just gonna have to plough through it...

[gnorwebthgimi]

Campden will help reduce the effects of 02 and so long as you have it ground up and ready to put in the barrel having the top off for one or two seconds is unlikely to introduce a noticeable amount of 02.

If it's over a month old and it's still drinkable then assuming it's

1. not keg conditioned with priming sugar

2. Reasonably low in IBU

Then it could just be age and it shouldn't get much worse. Just drink it so long as you enjoy it or brew another.

If it has been keg conditioned or has a high IBU, then I would be more worried that this is NOT age and COULD BE an infection and would keep an eye on it to make sure I knew what the issue was BEFORE getting rid of it because not knowing is hell.

Acetobacter requires oxygen to do it's work and I don't think it will progress much in the barrel without oxygen, so it still could be an issue.

[grmills]

If you've got any green/sweetish beer to hand make a blend, start with 50/50 then adjust according to your preference. Can be a cracking pint.

[Rowang]

Iv had a go with a campden tablet, recapped the keg and am currently trying to repurge the air! How long before its drinkable again post campden?

[gnorwebthgimi]

24 hours.

[Rowang]

cool, Thanks for the advice guys!!

[Kev888]

Just wondering - you say that you've had a week off, is that a week with a mostly full barrel or a week with only a bit in?

Just that it will go off much more quickly if there's not a lot in there, so in that time it could be normal going-off type behaviour unless the smell is quite obviously wrong.

Cheers,
kev