Is a vinegary smell always an infection?

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Jambo
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Is a vinegary smell always an infection?

Post by Jambo » Fri Jan 20, 2017 6:12 pm

Hi all

I dispense through corny kegs and must admit I'm pretty lazy in that when they're empty I often just leave them with the dregs in them until I have something needing kegged. This can be several months.

When I open them to clean them, the yeasty sludge at the bottom often smells pretty vinegary.

My beer always tastes great without any hint of vinegar.

I'm aware that Brett is pretty slow growing so is it possible that I have a low level of infection going on and my pitched yeast always out competes it and the beer tastes fine, but over several months it manages to get somewhere?

Or is yeast smelling vinegary eventually nothing to worry about?

Suppose it could also just be the nose stinging 'smell' of CO2...

Cheers

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Jocky
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Re: Is a vinegary smell always an infection?

Post by Jocky » Fri Jan 20, 2017 7:03 pm

I'd think that what you're getting is due to yeast autolysis, but vinegar or rather, acetic acid, in finished beer can come from acetobacter infection and can also come from extreme oxidation.

In extreme oxidation of finished beer ethanol reacts with oxygen to create acetaldehyde, which manifests as a musty/rotten apple type smell. When acetaldehyde further oxidises it breaks down to acetic acid.

If your beer is fine when drinking then I wouldn't worry.
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WalesAles
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Re: Is a vinegary smell always an infection?

Post by WalesAles » Sat Jan 21, 2017 6:26 am

Jambo wrote:Hi all

I dispense through corny kegs and must admit I'm pretty lazy in that when they're empty I often just leave them with the dregs in them until I have something needing kegged. This can be several months.

Cheers
Jambo,
I know that you are pretty and lazy, but why leave dregs in for months?
That is LAZY to the Nth degree! :D
You should be ashamed of yourself! :D

WA

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IPA
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Re: Is a vinegary smell always an infection?

Post by IPA » Sat Jan 21, 2017 8:47 am

I make vinegar as well as beer and believe me it is more difficult to make than beer. If the beer has an infection you cannot make vinegar with it because it kills the " mother vinegar' . It is also nigh on impossible to make white wine vinegar with commercial white wine due to the level of sulphites in it. If you are curious I make these vinegars because where I live you cannot buy malt vinegar or white wine vinegar and there is something special and satisfying about home grown shallots pickled in homemade malt vinegar.
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Jambo
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Re: Is a vinegary smell always an infection?

Post by Jambo » Sat Jan 21, 2017 9:55 am

WalesAles wrote:
Jambo wrote:Hi all

I dispense through corny kegs and must admit I'm pretty lazy in that when they're empty I often just leave them with the dregs in them until I have something needing kegged. This can be several months.

Cheers
Jambo,
I know that you are pretty and lazy, but why leave dregs in for months?
That is LAZY to the Nth degree! :D
You should be ashamed of yourself! :D

WA
Always thought I was pretty enough to get away with it!

Yeah you're right, wouldn't be a huge effort to give them a quick rinse when emptied!

Jambo
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Re: Is a vinegary smell always an infection?

Post by Jambo » Sat Jan 21, 2017 9:58 am

Jocky - thanks for the advice - I'll have a read about autolysis.

IPA - interesting stuff, that satisfaction appeals to me too... I tried to convert some awful cider into vinegar once and nothing happened!

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