Oatmeal Stout turned sour. Is it spoiled?

[eriver]

Hi guys,

I am fairly new to homebrewing, and very new to all-grain brewing. I've made some batches of extract (around 10) that turned out pretty good, so I decided to step up to all-grain. I've had two all-grain batches turn out good, and the third batch is the BYO Better Not Pout Stout recipe. Everything went well with mashing, fermentation and so on, but when I went to rack to secondary, I've noticed a pretty unpleasant (rotten-eggish) smell to the beer. After reading about it a bit, I decided to rack to secondary and let it be anyhow.

I had to go away and the beer sat on the secondary for about a month, until today I had time to bottle it. I racked it to the bottling bucket and took a sample to measure final gravity and give it a taste. The smell is not so prominent anymore, but the beer tastes very sour (the wort tasted sweet and delicious before fermenting). It doesn't taste bad per se (I'm pretty into sours), but I wasn't expecting it and I am not sure if it's good to drink or not.

This is the first time I had a batch go potentially spoiled, so I am not really sure whether to dump it or bottle it and drink it. Any thoughts/advice would be greatly appreciated! Thanks!

 

[thehaze]

Sour/vinegar taste usually indicates an infection, but not always.

May we have the grain bill, yeast, hop schedule, water profile and treatment, fermentation temp.?

Sour notes could also indicate a pH problem, especially in the mash. Roasted malt is acidic and the mash pH will drop and usually you need to bring the pH up again in the 5.3-5.6 range for dark, roasted beers. Not doing so, might drive your pH down and cause the sour notes.

Some yeasts, like SafAle S-04 is known to produce more lactic acid than others.

The yeast will actually determine the pH of the final beer, but it is related to the mash pH, which has great impact.

 

[GFHomebrew]

Sorry to hear Eriver if it is an infection let it go if you like sours it may just turn out good.

 

[Ozarks Mountain Brewery]

a Google quote from the page below

"That rotten egg smell can usually be identified as the gas hydrogen sulfide. It's the most obvious symptom that your beer has gone bad. It is the bi-product of the yeast strain or bacteria that have snuck into your brew (did we ever mention you've got to sanitize your equipment?)."

http://www.howtohomebrewbeers.com/2016/06/why-does-my-beer-smell-like-rotten-eggs.html

 

[J A]

Of course your wort was sweeter than the beer...the sugar has been metabolized into alcohol during fermentation.
If your "rotten egg" smell was just basically sulfur, it's not uncommon for even ale yeasts to produce that during fermentation at certain temps. The fact that it's gone makes me think that there might not be as much to worry about there.
I've gotten very tart notes from certain grists and hops with S-04 but you could very easily have picked up a little friend along the way in transfering or handling. Whatever it is, it's still beer and once the PH is at a certain point, there isn't too much that can happen to make it unsafe to drink...maybe unpalatable, though.
What's your FG?...if it went more than high 70s in percentage of attenuation, you may have something besides the yeast at work. I've never gotten much more than 75% or so from S-04. If it didn't develop a pellicle, though, it's probably okay.

 

[Nosybear]

How sour is it? Beer naturally becomes more tart as it ferments, a pH of around 4.2 is normal for non-soured beers. You said it didn't taste bad.... If it's an infection, it might get worse over time and start developing other aromas but as long as you can stand it and like it, it's safe to drink. Whether you want to or not is up to you.

 

[Pinfold]

Just a possibility... but I had a stinker of a tropical stout that actually came good (well drinkable in an interesting kind of way) after about 6 weeks. In the end I put it down to what the style guides would call ‘inappropriate hopping’. It was a leftover situation and I thought I’d just throw 40g of Summit in at flameout!

 

[ACBEV]

I'd say bottle your beer and leave for 4-6 weeks. When opening a bottle use your judgement (smell and taste), before drinking.

 

[J A]

When opening a bottle use your judgement (smell and taste), before drinking.

If it's bad enough to not be drinkable, it'll probably gusher up like a science project volcano before you can even get it close to a glass.

 

[ACBEV]

True they might do...

Reminds me when I made cider bombs, I added 6L fresh apple juice and sugar to a fermented 20L batch for bottling.

 

[sbaclimber]

I added 6L fresh apple juice and sugar to a fermented 20L batch for bottling.

I've over-carbed quite a few times (knock on wood, no bottle bombs so far...), but holy hell that's a lot of sugar post-fementation!