Need Help w Acetaldehyde (I think)

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wdavis2003

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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
 
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.
 
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
 
How much/what yeast are you pitching?

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

How do you transfer from kettle to fermenter?
I'm just pitching a packet of 34/70 for lager and 2 packets for my higher gravity Cold IPA. 34/70 tears through the wort but like I said previously, I'm very patient with my fermentation and even slowly ramp it up 2 degrees per day until 65-68 once final gravity is reached. No rehydration or a starter. Shouldn't be needed according to their instructions.

I just open the bottom port on my kettle and let it flow! Sometimes I use a strainer. Also haven't infused wort with O2 the last couple of brews because my O2 tank that I thought was new turned out to be an empty.
 
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.
Well I'm doing a Munich Helles and chose S-23 this time. Hoping for better results.

I THINK it's acetaldehyde. In past brews the odor was of green apple but not necessarily the taste (did seem to taste more over time) but this latest brew definitely has an acidity to it like a cider.

I've pulled the keg from the kegerator and will let sit for a week at room temp to see if I can get the yeast to finish up. From what I read, that could help. Only time will tell
 
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?
Last 2 batches I've not oxygenated the wort. My supply of O2 I thought I had were both empty.

I use a tilt and calibrated the temp and gravity before this last fermentation. Gravity (and likely temp) were both off the previous batch.

I'm not measuring wort ph. I rely on brewers friend water chemistry calculator. I believe I have been getting good results on water chemistry. However, this last batch, thanks to the apartment brewer, I just did spring water and a couple of milliliters of lactic acid. I think I'll go back to adding the brewing salts like before but I don't think that's the issue here as it's persisted through multiple brews.

Kolsch (1.048-1.012) Kolsch yeast at 62 for nearly two weeks then slowly ramped to 68. This brew was fantastic at first but competition said it was estery which I did start to notice

Festbier (1.056- 1.009) 34/70 at 52. After several days ramped up to 56. Then every few days I bumped it a few more degrees until rest at 68 for 2 days then cold crash. Beer was ok at first but had that green apple ester then tasted vinegary after awhile

American Lager (corn) (1.047- 1.012) 34/70 pretty much same fermentation as the festbier. Apple ester and then I threw out after a couple of weeks of no changes

Cold IPA (1.061 - 1.013) 34/70 started at 62 and reached final gravity in 4 days. Ramped up to 65 and held for a few then cold crashed. Only kept this one in the fermenter for about 10 days. Don't think that's a good idea with this yeast. Same apple ester but stronger. Beer would have been lovely if not for it. Threw out.

CHANGED ALL COLD SIDE 'ROUGH SURFACES'

American Lager (Rice) (1.061 - 1.013) 34/70 No clue how the SG was so high. Guess 2 lbs of rice will do that. Only pitched 1 34/70 because I was expecting low gravity. 52 for about 4 days then bumped to 55 until about day 18. Cold crashed and kegged a few days later. Also this was first brew without adjusting water chemistry aside from lactic acid. Apple esters and acidity.

Important to note that all these brews tasted great coming out of the fermenter right at kegging EXCEPT the last batch. However, that tasted great about day 12. 6 days later it tasted of strong overpowering alcohol before kegging. That's why I changed my equipment because I thought there was an infection somewhere.

Feedback appreciated
 
Estou apenas lançando um pacote de 34/70 para lager
1 pacote de 11,5 gr ? Se a resposta for SIM, isso é insuficiente.

A ferramenta Brewfather recomenda 2 pacotes para cada 2,7 galões ou 10 litros

1 pack of 11.5 gr ? If the answer is YES, that is insufficient.

The Brewfather Tool recommends 2 packets for every 2,7 gallons or 10 litters
 
Last edited:
Last 2 batches I've not oxygenated the wort. My supply of O2 I thought I had were both empty.

I use a tilt and calibrated the temp and gravity before this last fermentation. Gravity (and likely temp) were both off the previous batch.

I'm not measuring wort ph. I rely on brewers friend water chemistry calculator. I believe I have been getting good results on water chemistry. However, this last batch, thanks to the apartment brewer, I just did spring water and a couple of milliliters of lactic acid. I think I'll go back to adding the brewing salts like before but I don't think that's the issue here as it's persisted through multiple brews.

Kolsch (1.048-1.012) Kolsch yeast at 62 for nearly two weeks then slowly ramped to 68. This brew was fantastic at first but competition said it was estery which I did start to notice

Festbier (1.056- 1.009) 34/70 at 52. After several days ramped up to 56. Then every few days I bumped it a few more degrees until rest at 68 for 2 days then cold crash. Beer was ok at first but had that green apple ester then tasted vinegary after awhile

American Lager (corn) (1.047- 1.012) 34/70 pretty much same fermentation as the festbier. Apple ester and then I threw out after a couple of weeks of no changes

Cold IPA (1.061 - 1.013) 34/70 started at 62 and reached final gravity in 4 days. Ramped up to 65 and held for a few then cold crashed. Only kept this one in the fermenter for about 10 days. Don't think that's a good idea with this yeast. Same apple ester but stronger. Beer would have been lovely if not for it. Threw out.

CHANGED ALL COLD SIDE 'ROUGH SURFACES'

American Lager (Rice) (1.061 - 1.013) 34/70 No clue how the SG was so high. Guess 2 lbs of rice will do that. Only pitched 1 34/70 because I was expecting low gravity. 52 for about 4 days then bumped to 55 until about day 18. Cold crashed and kegged a few days later. Also this was first brew without adjusting water chemistry aside from lactic acid. Apple esters and acidity.

Important to note that all these brews tasted great coming out of the fermenter right at kegging EXCEPT the last batch. However, that tasted great about day 12. 6 days later it tasted of strong overpowering alcohol before kegging. That's why I changed my equipment because I thought there was an infection somewhere.

Feedback appreciated

Hmm, that last line makes me think it's not a fermentation issue at all. Acetaldehyde can also be be produced via dehydrogenation of ethanol. Do you have any copper in your system? Especially in your kegging equipment? It could be causing both ethyl acetate and acetaldehyde production from ethanol

https://pubs.acs.org/doi/10.1021/ac...l,production favors high-pressure conditions.
It can also be produced from oxidation of ethanol. Your kegging procedure sounds pretty good, but are you opening your fermenter at any other time during fermentation? also, have you checked your CO2 source? If you are getting particularly low-grade CO2 it could contain a higher level of air impurity
 
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
It was 34/70. I'm also trying to make a great lager. I switched the Bootleg lager yeasts. My recipe still needs work, but no more green apple.
 
1 pacote de 11,5 gr ? Se a resposta for SIM, isso é insuficiente.

A ferramenta Brewfather recomenda 2 pacotes para cada 2,7 galões ou 10 litros

1 pack of 11.5 gr ? If the answer is YES, that is insufficient.

The Brewfather Tool recommends 2 packets for every 2,7 gallons or 10 litters
Only 1 packet per 5 gallon for low starting gravity beers. Maybe I should up to 2 even though it tears through 5 gallons in 4 days?
 
Hmm, that last line makes me think it's not a fermentation issue at all. Acetaldehyde can also be be produced via dehydrogenation of ethanol. Do you have any copper in your system? Especially in your kegging equipment? It could be causing both ethyl acetate and acetaldehyde production from ethanol

https://pubs.acs.org/doi/10.1021/ac...l,production favors high-pressure conditions.
It can also be produced from oxidation of ethanol. Your kegging procedure sounds pretty good, but are you opening your fermenter at any other time during fermentation? also, have you checked your CO2 source? If you are getting particularly low-grade CO2 it could contain a higher level of air impurity
I actually did think about my CO2 source. I've recently got it from welding supply place. I think i will be filling up at my local homebrew store from now. I actually didn't know the homebrew store existed until my other one closed.

To answer your other questions, no copper. All stainless steel. Hmm actually I take that back. My pump has 2 copper fittings I place on the in and out to attach the tubing so I can recirc the last 10-15 of the mash.. and I actually just started doing that the last few brews. I think they came with the pump. Should I replace or can I dump in boiling water to clean?

I never open my fermenter but I did drill a hole for a spigot to transfer using a low oxygen method. I've always wondered if that could introduce oxygen but I've seen the same setup on many other fermenters. If I have to dry hop, I do the magnet method.
 
It was 34/70. I'm also trying to make a great lager. I switched the Bootleg lager yeasts. My recipe still needs work, but no more green apple.
Interesting. I've ordered s-23 for the new batch I'm doing this week. I almost want to not change any other processes just to confirm it was the yeast. I think I might
 
I'm just pitching a packet of 34/70 for lager and 2 packets for my higher gravity Cold IPA. 34/70 tears through the wort but like I said previously, I'm very patient with my fermentation and even slowly ramp it up 2 degrees per day until 65-68 once final gravity is reached. No rehydration or a starter. Shouldn't be needed according to their instructions.

I just open the bottom port on my kettle and let it flow! Sometimes I use a strainer. Also haven't infused wort with O2 the last couple of brews because my O2 tank that I thought was new turned out to be an empty.

One pack for lager temps seems a bit on the low side for pitch rate. Just checked Fermentis and 80-120g/hl is 15.2-22.8g / 5 gallons.
https://fermentis.com/en/product/saflager-w-34-70/
Do you disassemble the ball valve on your kettle for cleaning? Nasties can hide in there and grow.
 
not seen any mention of Candida albicans, a Bad source of acytaldehyde, suffered from it in my youth and lost many a brew both ale and wine to it, all was well after finishing ferment but a week later all was spoilt, never realized I had aural candidiasis at the time. Candida likes warm weather and alcohol.
 
One pack for lager temps seems a bit on the low side for pitch rate. Just checked Fermentis and 80-120g/hl is 15.2-22.8g / 5 gallons.
https://fermentis.com/en/product/saflager-w-34-70/
Do you disassemble the ball valve on your kettle for cleaning? Nasties can hide in there and grow.
I don't disassemble the ball valve for every brew but recently disassembled, boiled and then replaced tape. There were some nasties in there. I also run boiling water through both ports on the kettle before every brew using my pump for at least 15 minutes
 
not seen any mention of Candida albicans, a Bad source of acytaldehyde, suffered from it in my youth and lost many a brew both ale and wine to it, all was well after finishing ferment but a week later all was spoilt, never realized I had aural candidiasis at the time. Candida likes warm weather and alcohol.
Never heard of this. I will do some research on it
 
I had a run of several undrinkable batches a few years back. Not sure if it was acytaldeyde, but it was one of the suspects. Very acid tasting, beyind "green apples" in my case. Like your batches, they tasted promising at first, then degraded.

I finally ended the problem by disassembling and thoroughly sanitizing ALL parts of system, and replaced tubing. I also baked plate cooler in hot oven. I did find some suspect slime behind the valve gaskets in the process. After that, I kept my sanitizing regime up at a higher level, and have never had the problem since.

In any case, hope you get to the bottom of it, I know how frustrating it can be.
 
I had a run of several undrinkable batches a few years back. Not sure if it was acytaldeyde, but it was one of the suspects. Very acid tasting, beyind "green apples" in my case. Like your batches, they tasted promising at first, then degraded.

I finally ended the problem by disassembling and thoroughly sanitizing ALL parts of system, and replaced tubing. I also baked plate cooler in hot oven. I did find some suspect slime behind the valve gaskets in the process. After that, I kept my sanitizing regime up at a higher level, and have never had the problem since.

In any case, hope you get to the bottom of it, I know how frustrating it can be.
Thanks @Dland. I think I will follow your advice and tear down everything. It sucks seeing having to throw what looks to be great beer down the drain.
 
**Update**

I switched the yeast to S-23 and pitched 2 sachets (probably still under pitched) and the beer tastes great after 5 days in the keg. I'll be lagering this for a little while but couldn't wait to try it.

I believe I was under pitching the 34/70 and stressing the yeast. However, I did tear down all my equipment and boiled what could be boiled and thoroughly cleaned everything else. Also, this was my first fermentation with the fermzilla. Those are the only changes to my process but I'm pretty sure it was the stressed yeast causing the off flavor. I may try 34/70 again and pitching an adequate amount although I'm a little timid to go back to that yeast.
 
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