Getting Rid Of Acetaldehyde

[manticle]

You have obvious experience of many things Greg but I'm presuming you have no personal experience of either glad wrapping or no-chill - only theory on which you are basing your claims.

When multiple people report a certain result (eg no-chill works, glad wrap works for actively fermenting beer* it questions at the very least an interpretation of a theory, if not the theory itself.

Science is always evolving - it is not stagnant.

Don't diss methods with which you are not personally familiar when there is much evidence (anecdotal/experiential 'evidence' perhaps but enough that it's at least worth testing).

Loads of people use glad wrap without getting noticeable acetaldhyde so to point the finger and say 'culprit there' is a bit simplistic. Possible culprit maybe. Definite - neither you, nor I can say that.

* For aging beer, I wouldn't recommend it.

Having said the above, I would consider oxidation as a very real possibility in why the acetaldehyde is appearing. That or unfinished beer - 14 days is irrelevant if the yeast hasn't finished and been given a chance to clean up. If you can taste acetaldehyde in the conditioning beer, it needs more conditioning in my experience.

 

[Sprungmonkey]

Acetaldehyde is also from oxygenation after ferment - you can purge it out with CO2 in the keg. may take a while if it is strong though

 

[Greg.L]

I actually did try glad wrap once, never again (I got lazy). My point is if you have a lid, why use gladwrap? It just doesn't make sense.

 

[kevin_smevin]

The fact is that even a tiny bit of oxygen is bad. O2 is a very strong oxidiser, that's how the name came. You may think that a beer saturated in co2 is safe, but there is such a thing as partial pressures, it doesn't matter how saturated the beer is with co2 it can still dissolve oxygen. The only protection is the rapid movement of co2 out of the container, as soon as that slows o2 starts to enter. I use an open fermenter for cider because I can't afford a big closed fermenter. A basic rule for all alcoholic beverage production is to keep air out, there are a few special exceptions but beer isn't one.

If you think that glad wrap is sufficient protection for keeping air out then go for it, just don't complain when you get oxidation or infection. Most infections I see on AHB are aerobic in nature, caused by letting air in. If you keep air out of your beer the chances of getting a problem range from slim to zero.

Now just don't get me started on leaving your wort in no-chill cubes.

Plenty of people use glad wrap in place of a lid on their fermenter and dont seem to have any problems. I use a lid so i cant say i have any personel experience.

The common effect of oxygen in beer is wet cardboard and papery type flavours. Sherry like flavours do occur but seem to take a back seat to the afore mentioned. It would be rare to get sherry like flavours without the wet cardboard side of things. It is common in young beer to get the green apple type acetaldehyde flavours in the absence of typical oxidation flavours- if your yeast is healthy enough, it usually cleans these up in a few days.

If your beer is showing typical oxidation flavours such as paper, carboard/wet cardboard or sherry i would look at reducing exposure to air. If these green apple flavours are present in their absence i would suggest the problem is likely due to poor yeast health or possibly a contamination issue.

 

[Greg.L]

Acetaldehyde is also from oxygenation after ferment - you can purge it out with CO2 in the keg. may take a while if it is strong though

Once the acetaldehyde is bad enough, which is most cases, there is no cure. The cost of the co2 for a cure that probably won't work would be a real waste. Just tip it out and use a lid next time.

 

[Greg.L]

If your beer is showing typical oxidation flavours such as paper, carboard/wet cardboard or sherry i would look at reducing exposure to air.

See this is where people get things arse-about. You should be always trying to reduce exposure to air, not because you have a problem. Keep the air out and you won't get the problem, don't let the air in and wait for the problem.

 

[MaestroMatt]

I brew in a vacuum chamber so I don't have any problems with oxygen. Of course, I can't breathe when I brew, and I eventually lose consciousness and die.....so that part sucks

but the important thing is that my Gladwrap lid seems fine.

 

[daemon]

Have we got a contender for the the_new_new_darren Darren?

Greg.L: You seem to be a self confessed expert who hasn't really offered anything useful to the discussion and in contrast to what professional brewers have posted here. You've even disagreed with the "green apples" description, which means you'd be disagreeing with thousands of professional brewers around the world with far more experience than you. Seeing a trend here?

Please let us know how many PPM of oxygen that the glad wrap will allow to permeate through, especially considering the positive pressure of the co2. I have no doubt that glad wrap isn't as effective as the HDPE lid, but over a two week window (less for many) is it really that great of an issue? I haven't seen any evidence that positively concludes it is.

You've been doing it for 15 years without issue and that's great, but it doesn't mean that your methods or understanding is the only correct one.

 

[stakka82]

This has been a remarkably informative thread, despite, or perhaps because of, the 'vigorous' discussion.

I tried a pale ale of mine, all willamette, that had been in the bottle for only 7 days on the weekend. It was only half carbed but i couldn't wait to try it. Nice, but definite green apple character. Faint but noticable.

I wasnt sure if it was just the hops (never used willamette before this, and i had to put about 100 grams in a 22 litre batch to get a decent level of bittering) but reading here suggests it's an acetaldehyde issue. I'm going to try the batch again this weekend when its finished carbing, then cold condition all the bottles till I finish the batch.

Seems like I may have caught the conditioning yeast before they had cleaned up in the bottle? Does that sound correct? This thread also suggests that the conditioning time should fix the issue. Hoping it does.

 

[bullsneck]

I brew in a vacuum chamber so I don't have any problems with oxygen. Of course, I can't breathe when I brew, and I eventually lose consciousness and die.....so that part sucks

but the important thing is that my Gladwrap lid seems fine.

If you die from lack of Oxygen, I can't imagine how a kitten in an airlock would fare.

 

[kevin_smevin]

See this is where people get things arse-about. You should be always trying to reduce exposure to air, not because you have a problem. Keep the air out and you won't get the problem, don't let the air in and wait for the problem.

It's not ass about. You keep ignoring the fact that green apple from acetaldehyde is a normal part of beer fermentation. We're trying to understand the cause here. It could be oxygen exposure but it may have nothing to do with oxygen exposure. You are right, all brewers should avoid oxygen exposure post fermentation but in this instance it is not the only potential cause of the problem.

 

[manticle]

I actually did try glad wrap once, never again (I got lazy). My point is if you have a lid, why use gladwrap? It just doesn't make sense.

I think one big reason is to learn not to rely on an airlock as a sign of fermentation. That's where it starts.

Mostly convenience otherwise - clean one vessel and no accessories. It does make sense even if it's not your preferred method: However it doesn't make sense to condition beer that way for very long. Active fermentation only. I wouldn't be conditioning for ages with an HDPE lid either but some people do and report no issue. Long term beer gets racked to glass, short term stays in cube, tight lid, in fridge.

I mainly use a cube with a lid backed off during active fermentation so during conditioning I tighten the lid to reduce exposure to oxygen (I also no chill and ferment directly in the cube so you may faint over that one but I can tell you it works and it works very well: theoretically and practically).

I do agree with you that open fermentation will work best when it's active, not passive/conditioning and glad should be treated the same way. I don't agree that you can automatically point and say there's your issue because, in my experience, 14 days in primary with a glad lid will not automatically generate discernible acetaldehyde (which in beer often tastes like granny smiths or that toffee apple confecionery product you used to be able to buy around the place) and if loads of people do x and don't get y, it's not definite that x causes y.

 

[browndog]

Greg L. I'm not convinced about your oxygen-gladwrap-use a lid arguement. Many moons ago I threw away all the seals in my fermenter lids and just screw them on without the seal, I'm sure this would provide an oxygen superhighway compared to a well fitting grladwrap seal. Guess what, no issues with acetaldehyde here. Very interesting banter going on though.

-Browndog

edit:clumbsy fingers

 

[Greg.L]

Greg L. I'm not convinced about your oxygen-gladwrap-use a lid arguement. Many moons ago I threw away all the seals in my fermenter lids and just screw them on without the seal, I'm sure this would provide an oxygen superhighway compared to a well fitting grladwrap seal. Guess what, no issues with acetaldehyde here. Very interesting banter going on though.

-Browndog

edit:clumbsy fingers

Browndog, keeping out air is just a basic technique of brewing. You wouldn't brag about driving drunk, but you would probably get away with it. It's just not safe. Put the seals back on, show us you can do the right thing.

Glad to keep you entertained.

 

[WitWonder]

Perhaps here in all the banter I missed the answer to the question about open fermentations and why that practise still goes on today if it was the mother-of-all green apples? Also, the fact Greg has studied wine making which, coupled with "15 years" of homebrewing, has made him an expert on brewing is to my mind like suggesting an ear nose and throat surgeon should start treating cancer patients

 

[np1962]

I didn't know Viticulture was Winemaking B)

 

[Greg.L]

I doubt if anyone on this thread has actually tried a sample of acetaldehyde (myself excepted). Just because you think you have noticed "green apples" doesn't mean you know what acetaldehyde smells like, and it is a smell more than a taste. And yes, the viticulture degree does include winemaking.

 

[manticle]

Actually there's a few people (myself included) who have sampled acetaldehyde in the form of fault tasting kits etc. I'll be tasting it again week after this.

I don't think the 'sink the boot into greg because he's in the wine industry, not the beer industry' attitude is justified but neither is you suggesting that no-one here (and there are professional brewers who've posted in this thread) has tasted acetaldehyde samples.

 

[pk.sax]

How pissed are you tonight Greg?

 

[kario]

This has been a remarkably informative thread, despite, or perhaps because of, the 'vigorous' discussion.

I tried a pale ale of mine, all willamette, that had been in the bottle for only 7 days on the weekend. It was only half carbed but i couldn't wait to try it. Nice, but definite green apple character. Faint but noticable.

I wasnt sure if it was just the hops (never used willamette before this, and i had to put about 100 grams in a 22 litre batch to get a decent level of bittering) but reading here suggests it's an acetaldehyde issue. I'm going to try the batch again this weekend when its finished carbing, then cold condition all the bottles till I finish the batch.

Seems like I may have caught the conditioning yeast before they had cleaned up in the bottle? Does that sound correct? This thread also suggests that the conditioning time should fix the issue. Hoping it does.

Sure will....crack a bottle each month and test it. I had a batch that took 5mths to come good....and GOOD it was!