Acetaldehyde and bigger beers

[bannerj]

So, I'm a sucker for trouble and have been going for big beers after success with a pretty large porter. My trouble is getting the FG down to complete the fermentation.

I've got two beers bottled now and one about to be bottled that have missed their FG. Sweet with definite acetaldehyde.

For example, this rye tweaked Tripel: http://hopville.com/recipe/1688229

It's been in the bottle a good four months and will likely end up being more of a barely wine.

What is really happening in the longer conditioning of the bigger beers? I could taste some maturity of a bottle of the tripel in the last month. They yeast profile was more obvious with some esters peeking through the acetaldehyde. If I go another four months will much more of the acetaldehyde dissipate?

 

[bannerj]

bump

 

[SC_Ryan]

Acetaldehyde is one of the last compounds that the yeast clean up when they are done fermenting. If yeast is stressed or not at it's optimal health it can take a long time. Racking your beer off the yeast cake prematurely can cause acetaldehyde as well. Continuing to age those bottles will help. If it's still showing acetaldehyde after four months, it may never turn into great beer but is should continue to improve with time.

Focus on optimum yeast health going forward to avoid acetaldehyde. Proper pitch rate, pitching healthy cells and temperature control. Also, make sure you are choosing a yeast with higher alcohol tolerance for these bigger beers.

 

[PseudoChef]

Acetaldehyde is a precursor to ethanol in the fermentation cycle. So you're probably not pitching enough healthy yeast in your fermentations. If this is the cause, it won't go away unless there's active yeast.

Acetaldehyde can also develop through oxidation - ethanol can convert back to acetaldehyde. So check your racking/packaging procedures as well.

 

[Cyclman]

Great blog on this from Kai: http://braukaiser.com/wiki/index.php?title=Fermenting_Lagers#lagering.2Fcold_conditioning