Sweet vinegar taste?

[Catnip_X07]

Last year, on my 5th batch or so I had a problem with a Kolsch. Tasted very bad and was a sweet, urine/vinegar taste. Dumped it. Attributed to maybe the beer was too warm for fermenting (appeared to have a small krausen ring in the bucket)
In December of last year, same thing happened with a Schilling. I never did see any activity on it nor a Krausen, and the FG was off. Blamed it on fermenting too cold and maybe an old yeast packet? Dumped it as it was HORRIBLE.

I kegged my first cream ale on Thursday and tried it today. Disappointing, sweet urine taste. WTF! I've had several brews turn out great since the Kolsch and Schilling. Here is what I did, and maybe someone can out shout something.

1. Washed yeast from a successful batch. Yeast cake was about 6 days old, and was maintained with 1 inch layer of beer and stored cool.
2. Created starter from the washed yeast. Nothing appeared out of the ordinary. Starter was on stir plate for 24 hours.
3. Sanitized everything before, during and after boil. Meticulous cleaning.
4. Sampled wort and was .002 higher on OG than what I was planning. Dumped yeast starter into bucket.
5. On Day 2 I did not see any activity. very minimal krausen on top of wort (like a peach fuzz). I dumped in more yeast that had been washed.
6. Day 3, very active fermentation and decent krausen. Temperature range of 62-65 degrees.
7. Day 24, opened bucket. No funky surface issues nor any indication of bacterial infection . Sampled and FG was spot on. Sample had the slight vinegar taste.
8. Day 3 in keg, and poured first glass. Beer did not look right, and has a mild sweet/vinegar taste (think of a coke zero mixed with apple cider vinegar...artificial sweetness mixed with a subtle rancid taste).

Only thing I can think of is yeast issues during fermentation? NO changes in sanitizing/cleaning as other batches have turned out just fine (aside from Kolsch/Schilling). Kolsch issue was a fresh tube of White Labs and no starter (aside from fermenting too warm). Schilling was from a packet of dry yeast and may have fermented too cool. This is my first issue with washed yeast, but then again I haven't had a yeast cake go that long before washing.

Anyone have any ideas? What would cause the sweet vinegar taste?

 

[Wyrmwood]

Oxygen can convert ethanol to acetic acid (what makes vinegar taste like vinegar). Typically, it is not desired, though it is key to sour beer styles. Perhaps your washed yeast was exposed to O2?

 

[Dogphish]

did you get a nice big/thick yeast cake from these "urine" beers?

 

[Rockape66]

O2 by itself cannot convert ethanol to acetic acid, but exposure could bring in an acetobacter. Acetobacters convert ethanol to acetic acid. Are you fermenting in a bucket? Acetobacter can be pernicious once it inhabits any equipment. It is recommended to not even make vinegar (which can be quite useful and healthful) in an area where you ferment other potables. If you are using a bucket, check for scratches. If you have them, obtain a new fermentation bucket, and use the old one to store sanitizer/cleanser or discard it.

 

[dfc]

My question is how do you know what urine tastes like?

 

[Wiezer]

And what exactly is "sweet urine"?

 

[Catnip_X07]

did you get a nice big/thick yeast cake from these "urine" beers?

Actually, I did not have a nice yeast cake. Quite minimal and not what I expected to see.

 

[Catnip_X07]

O2 by itself cannot convert ethanol to acetic acid, but exposure could bring in an acetobacter. Acetobacters convert ethanol to acetic acid. Are you fermenting in a bucket? Acetobacter can be pernicious once it inhabits any equipment. It is recommended to not even make vinegar (which can be quite useful and healthful) in an area where you ferment other potables. If you are using a bucket, check for scratches. If you have them, obtain a new fermentation bucket, and use the old one to store sanitizer/cleanser or discard it.

Yes, I used a bucket. This same bucket is one I used last that made the horrible Schilling, but since then I had 3-4 beers come out just fine. So it could be the bacteria found in a scratch that wasn't able to get sanitized? If this is bacteria, shouldn't I have seen this on top of the beer when I opened it up?

 

[Catnip_X07]

I'm about to leave for a month or two and was thinking I could leave CO2 hooked up to the keg. Should I expect the beer to overcome this awful taste and turn out great when I return?

 

[Catnip_X07]

OK. Well, it's been nearly 7 months sitting in my kegerator with CO2 feed. Tried it tonight. Finally! It has a nice, cream taste initially, followed by an aftertaste that is way off. Aftertaste is a stale, or flat like beer. I'm happy in that it's no longer a sweet vinegar taste. I will bottle this soon so I can get space for my better brews. It seems that time, and being away to keep me from f'ing with it has helped turn the beer.

I thought back to the causes of this...would not shaking/stirring the wort adequately or thoroughly after I topped off with 2 gallons of water been a factor?

 

[Cosper123]

no, diffusion would naturally mix everything if left alone to itself as is...add yeast and all the movement that causes in at least the first few days, and it would mix itself quite well.