[benamcg]

Brewed a 10 gal. all grain batch of Imperial IPA at the end of January.  I had 28 lbs of malt (pale, crystal, flaked barley, special roast) and 3 lbs of turbinado sugar (to add gravity without the body).  Ended up being more like 8-9 gals in the fermentor- Needless to say I saw a new part of my hydrometer (1.114).  Pitched a lot (800 mL) of washed yeast (one because of the size, two because it was almost 2 months old).  Just transferred to the keg after dry hopping (FG= 1.010).  As usual, I drank the FG sample.  It tasted a little like green apple.  I am quite meticulous about my "lab practices" so I do not expect an infection (although it was the 1st thing to cross my mind).  Second thought was "young beer", and the third thing too cross my mind was the possibility of the effects of the turbinado (these two thoughts are what I am leaning towards - knowing that both should mellow with time).  I guess another possibility could be the yeast- but they did their thing. 

I would love to hear anybody's thoughts on the subject.
Thanks
Ben

[hopfenundmalz]

Yoiu said it is young.  Give it some time.  I hope you have some yeast to clean up the green apple.  I have used sugars up to 20% and there were no problems.

[benamcg]

Yoiu said it is young.  Give it some time.  I hope you have some yeast to clean up the green apple.  I have used sugars up to 20% and there were no problems

How much yeast is needed to clean up the green apple?  I transferred half of the batch (1 carboy) to a keg.  Obviously there is some yeast in there, but it is not sitting on the yeast cake anymore.  The other carboy will get bottle sometime this week and is still on the yeast cake.  I would think that the longer it sits on the yeast cake, the more likely off-flavors would develop from sitting on beat-up yeast.     

[bonjour]

Pitched a lot (800 mL) of washed yeast (one because of the size, two because it was almost 2 months old). 

Just transferred to the keg after dry hopping (FG= 1.010).  As usual, I drank the FG sample.  It tasted a little like green apple.  I am quite meticulous about my "lab practices" so I do not expect an infection (although it was the 1st thing to cross my mind).  Second thought was "young beer", and the third thing too cross my mind was the possibility of the effects of the turbinado (these two thoughts are what I am leaning towards - knowing that both should mellow with time).  I guess another possibility could be the yeast- but they did their thing. 

I would love to hear anybody's thoughts on the subject.
Thanks
Ben

acetylaldehyde usually comes from under performing yeast
Old yeast - possible cause
88-89.5% attenuation 8-9 gal  (compensating for the sugar
Seems like you had really good performance,  What were you timings, How long prinary, secondary etc.

[1vertical]

My only encounter with acetylaldehyde was resolved by waiting....if finally diminished
to nothingness but it took some time. It was when I used S-33 yeast...FWIW.

[benamcg]

Seems like you had really good performance,  What were you timings, How long prinary, secondary etc.

Normally I transfer to a secondary for dry hopping (and normally I use flowers)- this time I switched up protocols.  I pitched on Jan. 29th, let the fermentation go (went strong for several days with little lag- everything seemed fine), added pellets on Feb 5th, and transferred to keg on Feb 14th.   

I do prefer a transfer to secondary (clean vessel), but after reading lots of posts against it, I decided to give the no transfer a try.  We will see.

[dmtaylor]

Hey!  I was just reading that acetaldehyde has a boiling point of 70 F.  Then I went to Wikipedia which confirms that it boils at about 68 F!  In other words, if you warm up your beer to about 75 F for a few days, similar to a diacetyl rest, I would imagine that at least some of the acetaldehyde will bubble out.  So the trick here might be to WARM up the beer, NOT COLD CONDITION.  I don't see why this wouldn't work.  It might not be 100% effective, but should be at least partially helpful.  It can't hurt to try!

[benamcg]

Hey!  I was just reading that acetaldehyde has a boiling point of 70 F.  Then I went to Wikipedia which confirms that it boils at about 68 F!  In other words, if you warm up your beer to about 75 F for a few days, similar to a diacetyl rest, I would imagine that at least some of the acetaldehyde will bubble out.  So the trick here might be to WARM up the beer, NOT COLD CONDITION.  I don't see why this wouldn't work.  It might not be 100% effective, but should be at least partially helpful.  It can't hurt to try!

I think that if the taste doesnt go away I will give it a shot.