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End of fermentation off flavor

Anyone know of any off flavors that happen after terminal gravity is reached? I’ve had quite a few beers that taste great right when they finish but then by the time I keg, which is usually around 18-21 days, they end up with an off flavor. I can only describe it as acetaldehyde. I know that can happen from taking it off the yeast too soon but I just kegged one that’s 26 days old from the primary. The beer went from 1.053-1.012. May not be acetaldehyde but it seems green appley. Or maybe medicinal.

You extract or AG. What kind of water?

Also beer style, name of yeast and fermentation temperature?

All grain, not sure if it’s coincidence but seems to only be with IPAs. My water is :
Ca 24
Mg 6
Caco3 70

I usually let the beer temp get up to 68-70 then go a degree or two higher when it’s done. I’ve read most ferementation off flavors are produced early on. I just looked at notes, 18 hrs after pitch beer temp was 69. This one started within 6 hrs of pitch and was done in about 3 days at 1.012. Five days after pitch it tasted great. This sat in primary for 3.5 weeks.

This one is a pale ale but I’ve had this before with IPAs.

Any chance there could be some oxygen being introduced? Hoppy beers oxidize real easily, and oxidation, while sometimes being the carboardy flavor, can also basically cause intermediate compounds produced during ferment, then reabsorbed, to reappear (such as acetaldehyde). I’ve had acetaldehyde before w/ IPAs where I wasn’t purging the keg with CO2…early on the beer was great, then I tasted acetaldehyde later.

[quote=“RiverStreet”]All grain, not sure if it’s coincidence but seems to only be with IPAs. My water is :
Ca 24
Mg 6
Caco3 70

I usually let the beer temp get up to 68-70 then go a degree or two higher when it’s done. I’ve read most ferementation off flavors are produced early on. I just looked at notes, 18 hrs after pitch beer temp was 69. This one started within 6 hrs of pitch and was done in about 3 days at 1.012. Five days after pitch it tasted great. This sat in primary for 3.5 weeks.[/quote]

Are you using a municipal water supply? If so how are you treating it for chlorine or chloramines?

This is what I’m thinking. It’s the only thing that makes sense given that the off flavor shows up late.

[quote=“flars”][quote=“RiverStreet”]All grain, not sure if it’s coincidence but seems to only be with IPAs. My water is :
Ca 24
Mg 6
Caco3 70

I usually let the beer temp get up to 68-70 then go a degree or two higher when it’s done. I’ve read most ferementation off flavors are produced early on. I just looked at notes, 18 hrs after pitch beer temp was 69. This one started within 6 hrs of pitch and was done in about 3 days at 1.012. Five days after pitch it tasted great. This sat in primary for 3.5 weeks.[/quote]

Are you using a municipal water supply? If so how are you treating it for chlorine or chloramines?[/quote]

Yes it is municipal supply and i treat with campden.

I was just going to ask, how long has this been going on? Is there any changes to your procedures you have done, or maybe a new or different ingredient, equipment, something along those lines, just asking.

I’ve increased my fermentation temp but as far as I know any off flavor due to that would be created early not late.

Chlorine or chloramines in your water can do that. Also using bleach. What type of yeast are you using ?

I treat the water with campden. Hoping that’s taking care of the chlorine. I’ve had the problem on batches with wlp001 and this pale ale was dry us05.

My money’s on oxygen somewhere post-fermentation.

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