Will acetaldehyde via infection age out?

[Safa]

TL/dr: I have a milk stout that I suspect of having picked up an acetaldehyde flavour from bacterial infection during bottling. Will this flavour ever age out? It's kind of undrinkable right now.

Background:

• First batch of wine: tasted WONDERFUL at bottling, a few weeks later, the whole batch tasted like vinegar.
• Made a cream ale that now tastes like cider after a week or two in the keg
• Made the milk stout in question, tasted AMAZING at bottling. Now, after conditioning, has a horrible grassy flavour. (It was on the yeast for 4 weeks, so that rules out premature removal)
• I know that oxidation is said to cause this, but I'm pretty careful when racking etc, so I don't think that this is it.

I'm going to have to PBW+Starsan the **** out of my equipment, I know, including kegs/ racking canes/tubes/testing equipment.

Bottom line is, I've heard that acetaldahyde will age out if it was obtained via too early bottling. This, I think, is from bacterial infection at bottling. Does anyone know if, in my case, this beer will ever be drinkable?

P.S: Apologies in advance to Revvy for attempting to self diagnose my beer!

 

[aiptasia]

TL/dr: I have a milk stout that I suspect of having picked up an acetaldehyde flavour from bacterial infection during bottling. Will this flavour ever age out? It's kind of undrinkable right now.

Background:

• First batch of wine: tasted WONDERFUL at bottling, a few weeks later, the whole batch tasted like vinegar.
• Made a cream ale that now tastes like cider after a week or two in the keg
• Made the milk stout in question, tasted AMAZING at bottling. Now, after conditioning, has a horrible grassy flavour. (It was on the yeast for 4 weeks, so that rules out premature removal)
• I know that oxidation is said to cause this, but I'm pretty careful when racking etc, so I don't think that this is it.

I'm going to have to PBW+Starsan the **** out of my equipment, I know, including kegs/ racking canes/tubes/testing equipment.

Bottom line is, I've heard that acetaldahyde will age out if it was obtained via too early bottling. This, I think, is from bacterial infection at bottling. Does anyone know if, in my case, this beer will ever be drinkable?

I'm not convinced that what you're tasting is acetylaldehyde. Green apple is what you should be tasting with acetyl, not vinegary sour. Vinegar sour is usually caused by a bacterial infection by such bugs as lactobacillus (and lots of others) or oxidation (gives the beer a very sherry or wine-like vinous flavor).

Unless you used very old grains or grains that were improperly stored (moisture problems), they're not prone to fermenting in the husk and developing aldehydes.

To solve your problem, I would just thoroughly clean and sanitize everything like you already plan to do and use the freshest ingredients possible. Also, if you're a liquid malt extract brewer, consider switching to Dried Malt Extract or just take the leap into all grain. I have noticed that LME develops a sour twang in my beers, probably from sitting in the can too long and/or picking up a bacteria somewhere and partially fermenting before use.

 

[unionrdr]

Acetaldahyde tastes like green apple,pumpkin,paint or cut grass. It causes hangovers,& can be caused by lack of adequate fermentation time,as it is a normal by product of fermentation. But low yeast pitch can cause it as well as some bacteria. Aceto bacteria are what makes vinegar. I keep my grains in the plastic bags they come in in my home depot bucket,which has a sealed lid. LME & yeasts in the fridge,hops sealed in the freezer. This'll go a long way to keeping your fresh ingredients fresher longer.

 

[Safa]

I'm not convinced that what you're tasting is acetylaldehyde.

I appreciate the response, but you're not correct. look, this is how it is:

Adetaldehyde is also a byproduct of the conversion of ethanol to acetic acid (vinegar) by acetic acid bacteria. If this is the cause of your acetaldehyde problems, it will probably be accompanied by a vinegar-like or cidery flavour and aroma.

My wine tasted vinegary because of an acetic acid bacterial infection. Search wine making sites if you don't believe me. My cream ale tastes cidery because acetaldehyde is a byproduct of the production of acetic acid by this very bacterium.

Also, acetaldehyde doesn't ONLY taste like green apples, its also been described as cut grass, green leaves, pumpkin, and latex paint. I took my cream ale to my LHBS guy who is a BJCP judge, without prompting he immediately came to the same conclusion as I had.

Acetaldahyde tastes like green apple,pumpkin,paint or cut grass.it causes hangovers,& can be caused by lack of adequate fermentation time,as it is a normal by product of fermentation. But low yeast pitch can cause it as well as some bacteria. Acet bacteria are what makes vinegar. I keep my grains in the plastic bags they come in in my home depot bucket,which has a sealed lid. LME & yeasts in the fridge,hops sealed in the freezer. This'll go a long way to keeping your fresh ingredients fresher longer.

Also, thanks for the response Unionrdr, however neither of you have actually answered my question. I know why the flavour is there, I'm working to prevent it in the future, all I want to know is: Should I expect the flavour age out of this batch, like it can do, for more common acetaldehyde problems?

 

[unionrdr]

From an infection bacteria,no. But from the usual causes,if it's not too heavy,yes,it can age out in primary & bottles.

 

[Safa]

Thanks Unionrdr, that's what I was looking for.

Unfortunate, since I suppose I'll have to dump this milk stout then. The cream ale actually tastes pretty good, almost like a summer shandy, but that milk stout is pretty gross.

 

[unionrdr]

Was just looking at your original post. Grassy flavors usually come from dry hopping too long. It can also come from old malts not properly stored. They can absorb moisture & get funky.

 

[Safa]

No dry hopping in a sweet stout, and malts were straight from LHBS (which I assume has reasonable quick turnover of grain).

Wish there were another answer, but I'm afraid I'm stuck with the bacteria theory.


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[unionrdr]

How did the grains look,smell & taste? How did they store them?

 

[Safa]

It's really not the grains.


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[unionrdr]

The reason I asked came from this,under "grassy"; http://morebeer.com/public/pdf/off_flavor.pdf