Kegged beer turned sour after a couple months

[Enemygod]

I'm hoping to get some opinions on why my beer turned sour after a couple of months in the keg. I kegged a pumpkin beer back in September and I never tasted any off flavors. This weekend I poured off a pint and it's definitely turned sour. This was the first pint I've poured in a couple weeks.

I have a stout that seems to be fine as well, but it's been in the keg about a month less (October).

The only thing I can really think of, is that I sometimes get lazy and don't sanitize the inside of my rubber faucet cap/cover after I pull off a pint.

Anybody have any ideas why it took so long for an infection to show up? Luckily the keg is almost blown, but I'd like to prevent this in the future if I can.

Thanks!

 

[TravelingLight]

That's weird that it took months at cold temps to go sour. I'm at a loss but subbing to see what others say. Regardless, after this one kicks I would do some serious cleaning on everything. Break down the keg and clean all the tubes and posts super well. Hell, I might even replace all my o-rings for sanity sake.

 

[brewshki]

Sometimes, the beer in my lines goes a little funky but the beer in the keg is normal. Not really sure what it's from. Have you tried pulling off a few pints?

 

[augiedoggy]

I know whenever I made a pumpkin beer it would go funky If I didnt finish it off in a few months... are you sure its an infection or is it just past its prime? its always been refrigerated right?

 

[brewshki]

I know whenever I made a pumpkin beer it would go funky If I didnt finish it off in a few months... are you sure its an infection or is it just past its prime? its always been refrigerated right?

That's a good point. I've had a thanksgiving spiced beer that definitely was passed it's prime and it had a sour ish taste but definitely wasn't infected.

 

[Enemygod]

Sometimes, the beer in my lines goes a little funky but the beer in the keg is normal. Not really sure what it's from. Have you tried pulling off a few pints?

I have not tried pulling off a few pints. Just the 1 pint. I should do that, just to see. That would actually make me happy if the keg was good and it was just the beer in the line. Thanks for the suggestion.

 

[Enemygod]

I know whenever I made a pumpkin beer it would go funky If I didnt finish it off in a few months... are you sure its an infection or is it just past its prime? its always been refrigerated right?

It has always been refrigerated. In the keg then straight to the keezer. No, I'm not sure if it's infected or just past it's prime. I just know there is a definite sour funk now, that was not present a couple of weeks ago.

 

[user 125772]

The same thing happened to me a couple years ago, only it was a stout. I never fully determined what caused it, but assumed it was either some sort of wild yeast or bacteria, or, the beer oxidized .

Always purge the headspace in the keg withe co2, and ensure the couplers and keg are sanitary when tapping for best serving life

 

[brewshki]

Have those beer lines been cleaned recently?

 

[Enemygod]

Have those beer lines been cleaned recently?

I clean the lines whenever I tap a new beer. So the last time the line was cleaned was back in September when I tapped the keg.

 

[stella_tigre]

Hmmm, just dumped some punkin ale because it was tasting sour. It was fine at Thanksgiving but we decided to hold it until Xmas. It was in the fridge the whole time. Was very fizzy, the first pint pulled, and had just a hint of a sour flavor, so we decided to not keep it. (It was a 1 1/2 gal batch of which maybe a gallon was left.) We clean the lines every time, and this was the only batch so far (out of a dozen +) with an issue. I did pull apart the faucet, and will be extra vigorous with sanitizing before next use.

 

[steved53]

I'm not suggesting that it has anything to do with beer going sour in the keg (although it may be possible), but how often do people clean their taps?

I stripped my flow control tap down, after a few kegs of beer through it, and it looked gross - like a brown algae had taken hold. It only takes a few minutes to strip down and clean, so now I do it very regularly. My tap is fitted directly to the out post on the Cornelius keg, so no lines to consider.

 

[Enemygod]

Good question. I normally pump a continuous Oxy clean solution through my tap for 20 minutes, then follow it up with a Starsan solution for another 10-15, but I've never broken down the actual faucet to clean. Of course I've only had my keezer for 6 months or so at this point.