Need Help w Acetaldehyde (I think)

wdavis2003

I'm at my wits end. Can seem to brew a beer that doesn't smell like green apples. From the research I believe it's Acetaldehyde. I've recently changed all my cold side plastics. My first brew after has it and it may be worse then before. I use a plastic bucket fermenter. I transfer from the bucket using the low oxygen method of cleaning and sanitizing a keg then pushing the sani out using CO2 leaving an empty keg of CO2. Then transfer from plastic spigot on fermenter to beer out on the keg, while the IN post is pushing CO2 back into the top of the bucket fermenter. Like I said, everything that's plastic or rubber/vinyl has been changed and it's still there.
As far as fermentation I don't rush it. This batch of lager I left in the fermenter for nearly 3 weeks at 55 degrees. Doesn't seem to matter what style of beer, fermentation temperature or length of fermentation it's still there.
This is my first post. Let me know what additional info is needed.
Thanks

JohnSand

Welcome aboard.
Sorry that you're having this trouble. You might try searching "acetaldehyde" on this forum, I'm sure there will be many posts. I've had that problem with some beers and aged it out. I also had it repeatedly with a very popular yeast, so I stopped using it. Good luck.

wdavis2003

I will definitely research the topic. By any chance, was the yeast 34/70? I think I've used that for 4 brews in a row trying to dial in my lager and once for a cold IPA

marc1

How much/what yeast are you pitching?
How do you transfer from kettle to fermenter?

wepeeler

Acetaldehyde most likely is not coming from your equipment. It's from the fermentation.
You and I might be the only 2 people on the planet that can't get 34/70 to do what they want it to do. I can not make a decent beer with it. Wyeast 2124 made the best lager for me to date. I've also gotten good results with Imperial Harvest, making a LARGE starter. Also had good luck with S-23. Currently have a Festbier going with Wyeast 2206, so fingers crossed.
Seems like everyone talks about how well 34/70 does for them, people in my brew club included. I've tasted good beer with 34/70, just not my own.

TheMadKing

Acetaldehyde is usually a sign of poor fermentation health, so if you haven't tried a yeast nutrient, and more oxygen at pitch yet, I would recommend those.
Another thing to check is the calibration of your fermentation thermometer. If it's reading too warm, you could be fermenting colder than you intend and not helping your yeast to finish strong.
Are you doing anything to measure your wort pH and changing water chemistry?
If your pH is crazy high or low it could cause your yeast health to suffer.
Can you also post some of your OG, yeast strain, fermentation temps, for the bad batches?