Acetylaldehyde (Green Apple)

[jwible204]

so i was commissioned by a buddy to brew a Winter Warmer for a holiday party he's having. the party is 6 days from today. i brewed up a nice base recipe with some chocolate and crystal 60. it tasted absolutely fantastic after primary. i planned on adding spices while kegging when my buddy was around so we could taste together. i'd also like to point out that i bottled 2 beers after primary, while it still tasted awesome.

so, skip forward to kegging day, we crack open one of the bottles and it has this super acidic apple like flavor. we attributed it to the ginger addition in the boil and i thought it would mellow with time. so we transferred from secondary to keg, and it tasted exactly like the bottles.

fast forward 2 weeks, absolutely no change in flavor. so at this point i call my LHBS and on their advice i added krausen from another beer i had going. 3 days later the gravity hasn't moved and i pitched some T58. 3 days later, no change.

so i chilled and carbed the keg hoping it would change, it hasn't. i'm now thinking i'm just going to dump the batch. i have an all-Cascade Pale Ale as a backup that i just kegged and it tastes fantastic

any advice?

 

[HexKrak]

About what temp did you ferment at?

 

[jwible204]

Safale US04 @ 62-65 (ferm temp, not ambient).

i've used US04 for BierMuncher's Oktoberfast at this same temp and it was fine. the cause, i believe, is either an infection (though i've never had before) or because i pulled it off the yeast @ 1.019 because i didn't want it to drop any more.

 

[HeyNoPie]

I thought that type of flavor was due to not allowing the yeast enough time to clean up in primary. Do you know if your FG of 1.019 was stable? It may have still been fermenting then.

 

[jwible204]

damn, i thought i said this in my original post. alas, i did not. the ferm dropped to 1.016 while in secondary, and it stayed there for about a week before kegging.

 

[theredben]

That tells us that it was not finished fermenting yet, but with the additions of the krausen, and the extra yeast you will get good beer, but it just might not be ready for the christmas party.

 

[jwible204]

so should i keep it around in the keg and just wait it out?

 

[HeyNoPie]

I would say to wait it out, yes. I don't expect that it will be ready for the party though.

 

[jwible204]

sounds good, nothing wrong with a Winter Warmer in January/February.

 

[winvarin]

+1 to waiting it out. I had some problems with acetaldehyde last year when I began using temperature controlled fermentation for my ales. I was one of those poor, misguided souls using a calendar to dictate my fermentation. Lower fermentation temps do just what you would expect them to, slow things down.

The same can be said for a big beer like a winter warmer. The yeast need time to eat through the fermentables AND time to clean up any off flavors. Acetaldehyde is a precursor (to ethanol I believe ... chemists please fact check me on that one). Given enough time and sufficient quantity of viable yeast during the phase which follows your active (visible) fermentation, the yeast should clean up acetaldehyde.

If you've already kegged the beer, I would recommend keeping it at room temp (65F-72F in the winter at my house, depending on who had their hands on the thermostat last), and bleeding some of the pressure off every so often. I've also read where yeast tend to go dormant at higher pressures.

 

[bierhaus15]

Safale US04 @ 62-65 (ferm temp, not ambient)

I stopped using S-04 altogether because of supposed "acetyladehyde" problems. Tried everything under the book to remedy it, but nothing worked, and it never went away. Turned out it was just S-04 fermenting at a slightly higher temp and/or with a low pitch count, producing a very biting off flavor that I can best describe as having a buttermilk or yogurt acidity with an apple flavor. I dumped a couple of batches due to this.

 

[jwible204]

I stopped using S-04 altogether because of supposed "acetyladehyde" problems. Tried everything under the book to remedy it, but nothing worked, and it never went away. Turned out it was just S-04 fermenting at a slightly higher temp and/or with a low pitch count, producing a very biting off flavor that I can best describe as having a buttermilk or yogurt acidity with an apple flavor. I dumped a couple of batches due to this.

That's interesting. I've only used it for the Oktoberfast and now this batch. I think i'll stear clear, I just like the maltiness it brought out in the Oktoberfast (though that could be attributed to the 6 types of malt, haha) and it's super-flocculant.

Anyway, I'll see what happens in the coming months and dump it if it doesn't go away.

Edit - I did an Amber Ale yesterday and used Denny's Favorite with a 1 qt starter, I'm hoping it turns out and I can use that as my go-to for malty beers. Fermentation was absolutely crazy this morning.