Sour/vinegar taste in stout

This is the first time I've made stout, and I'm a little freaked out by what I now taste...I am ready to keg after 1 month in primary, and I tasted the beer after taking a sample for gravity reading. A week ago they tasted like stout (rich and malty), and now they taste like vinegar...

So, a little recap. I am actually making 2 types of stout. Both are made using BrewHouse Beer Kits: Stout. (Bag in a box).

Yeast is Wyeast 1099 (Whitbread) and Wyeast 1275 (Thames Valley). I used them both to make Pale ale kits 2 months ago. After I racked off into the keg, I just dumped in the new stout wort on top of the cake.

My diffusion stone wasn't working right when I pitched, so I stirred like a mother***** for 5 mins to aerate. (was a little nervous about this, as I'm usually paranoid about aeration)

Both beer took off well. And, after 1 month their gravities were 1.018 and 1.015.

No visible sign of infection. However, the Thames Valley one smells sweet, almost like a strong mead...

I was always careful to keep things clean, and sterilize everything with bleach mixture for 20 mins.

Does it sound like they are screwed? Should I dump them? Or should I just keg them and let them sit for another month? Or,am I looking at 10 gallons of vinegar??

If it's vinegar, that's an infection of acetobacter.

What is the bleach mixture you use?

I had battled this infection for about 3 months and from what I've read the acetobacter actually feeds off of the Co2. So, like you my beers were fine until I kegged them. After 2 weeks in the kegs, I had zero head retention, no hop flavor or aroma, and they tasted like vinager. My culprit was my CFC.

ranger - huh, I thought acetobacter was aerobic. do you have a link?

Bleach solution: 4ml to 1 litre of water

@Ranger - I haven't kegged yet..so no intro of CO2 yet...

@nateo - isn't it weird that BOTH plastic fermenters became infected? I was rinsing before swapping tools between containers...but maybe it wasn't good enough.

Apparently I just made that up because I can't find any reference to Co2 either. I had about 6 batches go bad that I had to dump and with almost all of them the beer tasted good/fine upon transferring to the keg. Once carbed it seemed to get much worse and was undrinkable at about 3 weeks. From my own experience it seemed as if kegging/carbing sent the infection into overdrive.

I'm not sure just bleach and water is an effective sanitizer. I could be wrong about that, but this is what I use:
https://www.homebrewtalk.com/blogs/...-bleach-water-vinegar-no-rinse-sanitizer.html

Edit: I actually alternate between bleach-water-vinegar and starsan to make sure I don't get any resistant bugs growing on my equipment.

According to a brewing network interview with Vinnie from RR, brett can clean up acetobacter. Could be worth a try.

@nofootbreak sorry, but can you elaborate?

@Nateo interesting...I'll have to try it out.

In this http://thebrewingnetwork.com/shows/596 interview, a caller mentions how a few batches of a brew his club made got infected with pedio and had acetobacter. The caller said one guy in his brew club pitched brett into his batch and it cleaned up the acetobacter.

I was just suggesting that if you would rather not dump it, or turn it into vinegar, you could try pitching brett and waiting until that ferments out to see if you still have the vinegar taste or not.

I think its worth a shot, but just remember you need separate tubing and plastics for bottling and such. I would let it ferment it out in glass too, to help keep oxygen out. Then bleach bomb the carboy after its empty.

Here are a few points:

1. Dark malts are more acidic than light malts. Your ph WILL be lower on stouts than lighter beers unless you add chalk or something else to raise the ph. You don't have to have an infection to have a sour stout.

2. You can still add chalk to decrease the acidity even after the beer is kegged.

3. Dark malts have more tannins. If your mash ph is not correct, you will extract tannins. However, this is more of a bitter, mouth-puckering taste. (Astringency - Like sucking on a wet tea bag.)

4. Some sour flavors will go way after aging. Do not dump the beer! Wait at least 3 weeks after kegging before giving up hope on the beer.

Chalk doesn't dissolve well. Slaked lime is much better for increasing alkalinity. But I wouldn't mess with pH unless you have the tools and knowledge to do so correctly. You'll just as likely do more harm than good.

The kind of sour you get from roasted grains is different from the kind of sour you get from lacto and is different from the kind you get from vinegar. I guess I can see how you might confuse them, but acetic acid (vinegar) is unmistakable to me.

You'll notice tannins on the back of your tongue, it's a dry bitterness like a red wine aftertaste.

Just general "sour" flavor may be the yeast still in suspension, so aging will help that, if that's the case, but to me, that doesn't taste anything like acetic acid.

Nateo said:

The kind of sour you get from roasted grains is different from the kind of sour you get from lacto and is different from the kind you get from vinegar. I guess I can see how you might confuse them, but acetic acid (vinegar) is unmistakable to me.

You'll notice tannins on the back of your tongue, it's a dry bitterness like a red wine aftertaste.

Click to expand...

Dark grains will decrease the ph, making the beer more acidic.
Dark grains can also increase the amount of tannins in the beer.

These are two very distinct differences.

LVBen said:

Dark grains will decrease the ph, making the beer more acidic.
Dark grains can also increase the amount of tannins in the beer.

These are two very distinct differences.

Click to expand...

I never said tannins and acids are the same. I said vinegar doesn't taste like lactic acid, and citric acid doesn't taste like burnt grain. So pH and flavor are only loosely related.

Ah, apparently, I interpreted your post incorrectly. I see now that you were responding to my 4 points with individual paragraphs. I thought you were describing the tannins as the acidity of roasted malts.