Vienna Lager acetaldehyde help...

[r2eng]

Just got my sheets back from NHC, and sat down to sample my Vienna Lager and compare my notes to the judges.

Before I read their comments, I cracked the beer and tasted it. This is not the same beer I mailed off last month: What the ???

One of the judges found acetaldehyde, and he is so right. What the heck happened? The beer did not have this taste in the keg, nor a few weeks before sending it (from bottles). I have read all about what it is and how it is formed, but the only thing that makes sense to me at this point is lagering at too cold of temperatures (which could be in this case).

It seems to me that acetaldehyde should have reared it's ugly taste earlier?

Has anyone had this issue and eliminated it? What are your thoughts?

 

[bja]

Last fall I had 8 full kegs of various beers carbed and ready to go. I decided to bottle a 12 pack from each keg so I could hand them out to friends. After a few weeks the same thing happened to all of them, sour vinegary taste. I know the bottles were clean, some were even brand new. The beer straight from the kegs was fine. The only thing I can think of is my picnic tap had something in it that caused this, even though I thought I had cleaned it well and sanitized it. What a waste of good beer.

 

[menschmaschine]

How does lagering too cold produce acetaldehyde? It seems more likely the beer was oxidized from transferring or bottling.

In any case, I believe you're SOL for this batch... however, you could consider krausening and that may clean some of it up... worth a shot anyway.

 

[r2eng]

Oh, it's way to late for this batch... good things it's only 2 more 12 oz'rs.

Ray Daniel's book states the "lagering too cold" thing. I doubt it's a sanitation issue, as there would be other things that acetaldehyde.

Shouldn't be oxidation, either: I transfer to sealed kegs to lager, and there is not much contact with ambient air.

I am thinking I should have let it on the yeast longer, and maybe the long lagering just made the acetaldehyde more prominent. It was most likely there all along.

Oh well, guess I'll have to brew it again and see what happens... dam the luck!

 

[remilard]

Late onset acetaldehyde is almost certainly from oxidation of ethanol or bacterial contamination. If the yeast didn't reduce the acetaldehyde to ethanol at the end of fermentation, you would have tasted it then.

It's possible it was barely there all along and you missed it until you read the judges comments, but if it is obvious now I doubt you drank 5 gallons of it with slightly less lagering time and missed it.