# alcohol content to prevent vinegar



## wood1954 (Dec 9, 2013)

If my port wines are 18-20% alcohol will that prevent it from turning to vinegar? I tried to find an answer online but couldn't come up with anything. Is there a limit to how much alcohol vinegar bacteria can tolerate?


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## WVMountaineerJack (Dec 10, 2013)

SOP is to use KM to keep vinegar away, without KM its just a matter of time before it gets you  WVMJ



wood1954 said:


> If my port wines are 18-20% alcohol will that prevent it from turning to vinegar? I tried to find an answer online but couldn't come up with anything. Is there a limit to how much alcohol vinegar bacteria can tolerate?


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## jamesngalveston (Dec 10, 2013)

Wine becomes vinegar when it's been contaminated by acetobacter bacteria...it consumes the alcohol and converts it to acetic acid.
Adding brandy raises the alcohol level in the wine to a point where it's toxic to the acetobacter bacteria...the bacteria cannot survive to consume the alcohol, etc.
This is where sherry and port originated. When transporting the wines over long distances (which took much more time), they'd fortify the wine with brandy as a means of preserving it. Generally, an alcohol concentration of over 18% is sufficient to keep most bugs away and preserve the wine for extended periods.


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## tingo (Dec 10, 2013)

James is this why vodkas and such dont need topping up as critically as wine does?


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## jamesngalveston (Dec 10, 2013)

i quess, i know that hardly anything can live in 40 percent abv are better...


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## Turock (Dec 10, 2013)

I agree with James, but vinegar is an oxidative process--meaning it takes oxygen to produce it. Acetobacter is everywhere so the way to prevent it is using sulfite and limiting your headspace so you don't have that oxygen exposure. Also, yeast produces small amounts of vinegar, so every ferment has a small amount of it.


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## seth8530 (Dec 10, 2013)

Actually, I think I read somewhere that even whiskies will degrade due to contact with excess oxygen.. However, I do not think the effect is quite as pronounced.. If anyone can verify this I would appreciate it.


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## jamesngalveston (Dec 10, 2013)

seth i have heard the same thing, but can not find much on it.
besides, once i open one, it will be gone pretty dang quick.


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