Unintentional sour - what happened?!

[milkit99]

So I was short on time but, more distressingly, short on beer earlier this year, so I did a couple of quick, dodgy partial kit brews so I could have something to drink.

One partial was a dark ale kit to which I added some black barley and chocolate malt. The sugars were 60/40 DME and dextrose. A few days later I dry hopped with a bunch of Citra I had lying around (doing a bit of a cleanout), and just used a pack of US-05. Going for a pretty rough black IPA.

Kept an eye on it for a short while, tasted it after primary - pretty meh, but whatever. Had that homebrew twang.

It was about then that I forgot about it. So it's been sitting in the fridge at a constant 20C since about April, hop bag and all. Never got racked out of primary.
For some reason I remembered it tonight, so I gave it a crack. Smelled surprisingly nice and mellow - amazed that there was still some pretty good hop aroma on there.

But the flavour - holy hell. Sour as all get out, with hoppy citra flavour and a good note of sweetness. Almost like a hopped kombucha.
Probably going to pour another right now - I can't work out if it's good. I do like my sours.

So I'm wondering - is there anything about leaving it on the yeast and the hops in primary for so long that would have soured it, or is there likely an infection in here somewhere that's done it? I didn't notice anything funky going on at any point, but then again I wasn't paying it much attention!

Cheers y'all!

 

[damoninja]

Leaving it on the yeast won't give you an infection, though I'm surprise the autolysis man didn't come in and get all up in your brew (sarcasm yeah I'm in autolysis disbelief some top brewers are too despite some beers being left months or years with no ill effects though apparently even if me or other great brewers can't taste them they could still be there but only detectable via spectroscopy so if you're giving it to a biologist look out)

So long as it was sealed up, in theory, it's not exposed to the outside... chances are the infection happened and wouldn't have made much difference if it was left in the fermenter or bottles. Keg maybe another story if it was in the fridge.

Did it have a pelicle?

Was the hop bag hanging around on the top exposed from the beer?

 

[peteru]

the infection happened and wouldn't have made much difference if it was left in the fermenter or bottles

A bacterial infection will consume things that yeast won't. If bottled the result would have likely been gushers or glass grenades.

You can pretty much bet that it was a bacterial infection.

If you don't find it undrinkable, bottle it and age it. You can always blend it later with another beer, just like the real lambics.

 

[manticle]

Disbelieving in autolysis is like disbelieving in evolution.

You can't see either and neither may noticeably affect your life (in which case why worry?) but that doesn't make it less real.

However sourness isn't coming from that direction if what you are tasting really is sour.

At that temp, unless fermenting under pressure, exposure to oxygen may have allowed lactobaccillus or another microorganism with souring capability to grow in larger numbers.

That's my guess. It is only a guess. If you like it, drink it but be wary of re-using that equipment for non sour.

 

[Fourstar]

i saw you added grain to the partial. im assuming you steeped and boiled the extraction? if not, thats a pretty likely source of lacto and other souring bugs.

 

[damoninja]

A bacterial infection will consume things that yeast won't. If bottled the result would have likely been gushers or glass grenades.

You can pretty much bet that it was a bacterial infection.

If you don't find it undrinkable, bottle it and age it. You can always blend it later with another beer, just like the real lambics.

Yeah good point really, I particularly meant to the taste opposed to the outcome, he'd likely have had no way of knowing they'd be gushers or so on that early in the piece.

Now you mention that I did have a beer that after about 12 months went all gushy, wasn't sour but was generally rank

Disbelieving in autolysis is like disbelieving in evolution

You can't see either and neither may noticeably affect your life (in which case why worry?) but that doesn't make it less real.

Put it this way I don't believe it doesn't or can't happen, I just don't believe it's OK to leave your beer 14 days but not 15 and 20 or if it does buy yourself a mass spec to you can figure out that you should bottle your beers at 13 days 8 hours 4 minutes and 58 seconds because any longer and BAM autolysis man to your demise.

By the analogy it's something that takes a long time to happen.

I suppose in theory it starts the moment you pitch your yeast as some cells will die right away,

 

[dannymars]

i saw you added grain to the partial. im assuming you steeped and boiled the extraction? if not, thats a pretty likely source of lacto and other souring bugs.

^^^ this

With a healthy pitch of yeast these bugs would take a little while to get a foot-hold in your beer... but, you did leave it for 6 months.

 

[damoninja]

^^^ this

With a healthy pitch of yeast these bugs would take a little while to get a foot-hold in your beer... but, you did leave it for 6 months.

Assuming he didn't boil it that's where my money would be, generally silly move looks like he joined in 2011 assume been brewing since at least then 5 years in you'd hope this isn't a mistake that's been made

 

[manticle]

Yeah good point really, I particularly meant to the taste opposed to the outcome, he'd likely have had no way of knowing they'd be gushers or so on that early in the piece.

Now you mention that I did have a beer that after about 12 months went all gushy, wasn't sour but was generally rank




Put it this way I don't believe it doesn't or can't happen, I just don't believe it's OK to leave your beer 14 days but not 15 and 20 or if it does buy yourself a mass spec to you can figure out that you should bottle your beers at 13 days 8 hours 4 minutes and 58 seconds because any longer and BAM autolysis man to your demise.

By the analogy it's something that takes a long time to happen.

I suppose in theory it starts the moment you pitch your yeast as some cells will die right away,

Of course it doesn't hit a cut-off and then automatically become a bowl of soap and vegemite. Like loads of things, it's dependent on many factors. Yeast health, wort gravity/alc level, temperature, etc.