massive acetaldehyde from bottle conditioning, can I still reuse yeast from the batch

[tyrub42]

Hi,

I just brewed a NE Pale ale for the purpose of harvesting Conan yeast. The beer came out beautifully, but after bottling it developed a MASSIVE acetaldehyde problem. I try a bottle a day after the first couple of days carbing up to monitor progress (typically I get full carbonation in about a week), and at first it was undrinkable. It was bad enough so that I assumed it was contaminated on day three when I first tried it. On the good side, it has calmed down A LOT over the course of 5 more days (been in bottles 8 days total) and shows no signs of contamination. On the bad side, I have no idea what caused it, no idea how to prevent it from happening again (aside from switching to kegging), and worst of all, I don't know if it would be a good idea to reuse the harvested yeast now. There are a few factors I can think of, but none seem like they would cause this problem:

-It's hot af where I am conditioning, high 80s-90. However, it's been like that over my last few batches, all with the same yeast, and all have turned out great.
-I am using t58 for bottling yeast, since my first batch with conan didn't carb in the bottles. It has proven to be great at sticking to the bottom of the bottle, carbing super quickly, and contributing no flavor. However, I am still on my first packet and it has been in a ziplock back with the air pressed out, which could oxygenate it I suppose. Any chance that could be it? With a very low FG and only a couple of days, contamination couldn't be to blame, but could the t58 be spoiled and give off such a strong A-hyde bomb as a result? Seems like a stretch but I don't know...

That's all I can think of. I actually let this batch sit on the cake several days longer than any other because of time constraints, and not only did it taste great at bottling; I just drank the beer on top of one of my mason jars of harvested yeast before dumping the yeast. It's light, fruity, hoppy, and perfect, so there was zero A-hyde in there before bottling (well...undetectable anyway).

After looking this up, most forum members suspected contamination with acetic acid bacteria in others' posts, but now that he beer is cleaning itself up and tasting passable with normal carbonation, seems like that wouldn't be the case. Any insight is welcome.

Lastly, I'm thinking I should dump the harvested Conan. It sucks because I was really looking forward to gen 3, but I don't want to risk ruining another batch just in case that is what's to blame. What do you all think? Dump it since something went wrong in bottle conditioning? Or keep it since the beer tasted perfect prior to bottle conditioning including right now off of the Conan cake?

Sorry for the long post. Feel free to just weigh in on whatever part(s) you feel like.

Thanks,
Tyler

 

[tyrub42]

Seems like this one seems to stump everyone I talk to, but just to be safe, I'm dumping the yeast. Just got some wlp007 delivered anyway so I can play with that for awhile. Acetaldehyde is mostly gone now, but the aroma still isn't close to what it was before this happened. On the upside the beer is a huge hit with everyone except me, and girls seem to love it especially, so it's at least a good 'Tinder-date beer' haha.

 

[ncbrewer]

At least you saved the beer. Brew on.

 

[tyrub42]

After reading up a bit, it could have had something to do with using table sugar instead of corn sugar. I've read lots of conflicting things, but it seems like table sugar can make some pale beers (70ish percent of what I brew) cidery. I'm thinking they probably sell dextrose here, so I'll see if I can find it.

P.S.- is there any difference between corn sugar and dextrose, or are they 100-percent synonymous (weight and chemical makeup)?

 

[Dcpcooks]

Have you read this yet?
http://beersmith.com/blog/2016/07/13/acetaldehyde-in-home-brewed-beer-the-green-apple-off-flavor/


It's more likely fermentation related than conditioning warm or your sugars. Do you control temps during fermentation?

It's very odd that you needed to add yeast to bottle condition with Conan in a neipa. That suggests poor health or poor temp control during primary.

Since it's cleaning up in the bottle with new yeast that suggests you bottled before the yeast could clean up. But that also means it needed the new yeast to finish up fermentation.

How are you collecting your yeast? How are you storing it and for how long.

 

[tyrub42]

Have you read this yet?
http://beersmith.com/blog/2016/07/13/acetaldehyde-in-home-brewed-beer-the-green-apple-off-flavor/


It's more likely fermentation related than conditioning warm or your sugars. Do you control temps during fermentation?

It's very odd that you needed to add yeast to bottle condition with Conan in a neipa. That suggests poor health or poor temp control during primary.

Since it's cleaning up in the bottle with new yeast that suggests you bottled before the yeast could clean up. But that also means it needed the new yeast to finish up fermentation.

How are you collecting your yeast? How are you storing it and for how long.

I don't think it's fermentation related for a few reasons, but the biggest is that there were no signs at all before the beer was in the bottle. So while the problem did clean up a bit in the bottles, it also wasn't there before it was bottled. It was just a juicy pale ale with tons of hop flavor and that wonderful conan ester profile. Even when I gravity tested on day 3 before dry hopping the only off flavor was extremely light diacetyl (and obviously extremely yeasty since it was still fermenting). This other problem was 100-percent made in the bottles, but I don't know what from...

Let me address your other questions one at a time, though.

-Yes, temp controlled. Temp is always raised to 68 after fermentation slows to almost nothing (about 5-6 days), then to 72 for 2-3 days before chilling and bottling. The first 4-5 days days were at 16-17c for conan (about 62-63f). My probe is taped to the side of the fermenter.

-The conan batch that didn't carbonate was first generation conan pitched at 1 day old, professionally grown in the best yeast lab in the country, at 400 billion cells (calculated that I needed 380). The acetaldehyde batch
was second generation, and was about a month old. I calculated according to mr malty and made a starter to revive the yeast before pitching.

-I collect yeast via the slurry method (swirling the yeast around with the leftover beer after transferring my beer to a bottling bucket), put into sanitized (boiled) mason jars, starsan the boiled lids before putting them on, and storing in my fridge. The first and second jar were also pitched and both came out flawlessly and conditioned great in the bottles (with the same added yeast). While I can't say whether or not the extra bottling yeast was necessary, having one batch not carbonate was enough for me to take the extra step in the future. I used t58 which safale recommends for bottling, and they were right that it works well (in the other three uses...). Carbed in days and the yeast sticks to the bottles like glue.

-also you didn't ask this but just to let you know, my bottles are all rinsed right after I drink them, then soaked in a bleach/ water solution for 24 hours, poured out, flushed with water 3-5 times, allowed to dry upside down, then stored. On bottling day, they are all soaked in starsan, shaken, and then drained. I leave the starsan foam in the bottles instead of letting them dry upside down, as it seems safer. I also soak my caps in starsan. all bottling equipment is sanitized as well.


So in short the really perplexing part here is that this was my third consecutive batch using the exact same methods of fermentation and bottle conditioning AND the same yeasts for both from the same generations, but only this one had any problem. The problem also only presented in the bottles and not in the finished beer prior to bottling. That's why I can only think that my yeast was 2 weeks older than the previous batch (but I used a starter, plus my beer was 10 gravity points lower than the previous batch), and my bottling yeast was not stored vac-sealed (I just put the packet in a ziplock bag). Neither of these should have done that, but they were the only differences.

As you can see, I'm grasping at straws here haha. As a precaution, I threw out all of the gen 3 conan that I harvested from the batch and threw out my packet of bottling yeast and will use a new packet next time and vac-seal it for future uses. I'm thinking about replacing my bottling wand and auto siphon as well, but I think i'll just take them apart and give them a long soak and cleaning for now instead (I ususally just run starsan through them for 10-20 minutes before and after use, but once ever few batches, I'll take apart and attack with soft brushes on wire).

I found dextrose sugar here and will use that in the future (it was 3 dollars for a kilo so it's affordable), but in all honesty I can't see how that would have been the sole reason for this either.

Anyway, thanks for the reply! If you still think there were any fermentation mess-ups to correct, please let me know. I'll go back to conan in a few months and see how it goes then.

 

[malhal]

Might not have been acetaldehyde might have been strong esters which happens with Conan at too high temps, the fruitiness was so powerful in my case it was verging on acetone. I reused the yeast from this batch and the gen 2 beer without using a high temp was fine. The reason for the high temp in gen 1 is it was stuck at 1030 (but it was a high gravity beer which gen 1 apparently struggles with so wish I had just went with it).