Does Acetylaldehyde stick to/in yeast

[PaulHilgeman]

I have noticed this brewing lagers over the last year.

When I have a beer in the fermenter, there is no green apple smell or taste, no Diacetyl etc, and it has been about 4-5 weeks, I go ahead and keg it. As it gets cold in the keg and I take a sample after a week or so to check for carbonation and general taste, I always get scared because I almost ALWAYS taste Acetylaldhyde.

A normal sample would be to discard the first 4-5 ounces of beer because it is very cloudy, the next 4-5 ounces are just a bit hazy, and I taste it.

Based on this, has anyone else noticed somehting similar, and does the green apple flavor tend to stick on/in the yeast?

As an aside, I pitch huge starters, ferment cold, pitch cold and ferment long and I always have detectable acetylaldehyde at some point before the beer is served. Is this common with Wyeast 2124, which is my go-to lager yeast.

Thanks.

 

[MachineShopBrewing]

You could have oxidation of ethanol going on. That will cause acetylaldhyde to show back up.

 

[PaulHilgeman]

I doubt that, I keg the same way every time, purged keg, drain staight from the conical to the keg, there really is no O2 contact at all. If that was the case, I would assume I would see it with other yeasts than 2124, and more often with higher alcohol beers, and this is not the case.

 

[MachineShopBrewing]

I doubt that, I keg the same way every time, purged keg, drain staight from the conical to the keg, there really is no O2 contact at all. If that was the case, I would assume I would see it with other yeasts than 2124, and more often with higher alcohol beers, and this is not the case.

I do mine basically the same way that you do and I have noticed acetylaldhyde show up on occasion on a well fermented beer. I even sent one in for judging that I suspected was oxidized and had a green apple flavor and a high ranking bjcp judge called it out exactly as oxidation of ethanol. It is something to look at at least.

This yeast is very consistent in the way that it produces sulfury and unwanted flavors at first and then after lagering three weeks it goes away and clears nicely. It is the force behind the finish of the beer no doubt. So don't worry, just wait two weeks. Not recommended for hoppy beers, the malt flavor 830 gets can be covered by over hopping.

I found this quote on the white labs site in the review section for wlp830 which is basically the same yeast. FWIW

 

[PaulHilgeman]

Interesting, thanks. It would be REALLY weird if I picked up oxygen somehow.

Why has the only beer that I have ever had that I knew was oxidized had the wet cardboard / sherry type flavors? It was bottled off a keg, and I forgot about it for 3 months, definitely was oxidized. Will this beer turn into that?

Thanks for the help. I find 2124 pretty hit-or-miss with regard to sulphur, doenst seem to happen every time for me, and certainly not strong sulphur like some other yeasts.

 

[MachineShopBrewing]

Why has the only beer that I have ever had that I knew was oxidized had the wet cardboard / sherry type flavors? It was bottled off a keg, and I forgot about it for 3 months, definitely was oxidized. Will this beer turn into that?

No idea as to why or if it will get the cardboard flavors. Mine that had the green apple didn't develop any cardboard flavors. They weren't around more than 3-4 months though. I am not sure of the chemistry behind it all, just that I knew they were well fermented and I took every precaution to avoid oxidation.

I have been completely going through all my cold side processes lately to minimize oxygen pickup even more. I added a gas only line to my manifold with a picnic tap on it and a tube shoved into the end ala Biermunchers bottle filler. I am using that to blanket everything possible with CO2 before doing anything.

Other places to look are how much residual sanitizer liquid is left in the keg when you are done. That water has oxygen in it. I'm not sure how much it matters, but there are a lot of little things like this that could add up. Dave Berg, headbrewer at Schell's told me once that you want to be under 50 ppb of oxygen after fermentation and into the package.


Of course, it could just be the yeast too. I used that strain a few times, but got a lot of sulpher the times I used it and switched to the Ayinger strain wlp833 which has been dynamite for me.