Cider turning acid

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doublejef

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Hi guys,

I think one of my cider is turning into vinegar.
The taste and acid titration is growing up since a few weeks. The blend was quite low at the beginning and titration give me a 4g/l. Now it's around 5-6 and I can really taste it.
Is there anything I can do to stop it? Sulfite should help? I may let to much air space during a few weeks. Now I reduce it to nearly zero but I'm affraid the damage is done.
I was about to blend it with another batch and bottle it but I'am affraid to waste all the blend with the one that is maybe infected.
Any thought?
 

gregbathurst

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The main thing with vinegar is the smell, it will give off a strong vinegary smell. It sounds like it probably is acetic acid, blending won't really help. Some people don't mind a bit of vinegar flavour, but really the only thing is to dump it. You could do a trial blend to see what you think. Making proper vinegar is long and difficult, you need to get the acid up near 5%, 50g/l.
 

FromZwolle

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if you keg and backsweeten, you might get away with neutralizing the acid with a little base addition. the bigger problem is the infection causing it. that won't go away and will need to be dealt with when cleaning equipment.
 
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doublejef

doublejef

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Thanks for the answer.

I did some thorough research and I read that when cider become vinegar, the acid developing into it is acetic acid that is very volatile. So it is possible to measure it taking a acid titration of a sample, take another sample and boil it quickly to remove the acetic acid and the take a new acid titration, difference between the two titrations give the quantity of acetic acid.

Acetic acid < 0,7g/l => all good
Acetic acid around 1g/l => start to be noticeable and may not age well
Acetic acid > 1,5 unpleasant

My test gave me 1g/l.

I can’t really taste or smell vinegar into my cider but I put a sample into bottle a few weeks ago and the I can taste it in there. I guess when I Bottled it the contact with oxygen made it grow faster.

Now I thinking about getting it out of the fermenter asap and maybe put it into keg and pasteurize.
 
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doublejef

doublejef

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Some more questions :

- Do you think sulfite can help if I put it now into the vessel?
When I take a sample directly from it, vinegar is not really noticeable so I read here and there that it may not be too late to stop it.

- If I keg it, I may also put sulfite when kegging and it will be also good? If yes, is it ok to add sulfite in the keg before pouring the cider?

- Bacteria need oxygene to turn cider into vinegar so if I do my best to avoid my cider to be exposed to O2, will it stop the process ?
 
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FromZwolle

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Some more questions :

- Do you think sulfite can help if I put it now into the vessel?
When I take a sample directly from it, vinegar is not really noticeable so I read here and there that it may not be too late to stop it.

- If I keg it, I may also put sulfite when kegging and it will be also good? If yes, is it ok to add sulfite in the keg before pouring the cider?

- Bacteria need oxygene to turn cider into vinegar so if I do my best to avoid my cider to be exposed to O2, will it stop the process ?
i don't think you can stop it completely, but no more o2 should slow it down to a slug pace. that being said, it will still keep eating the alcohol until all the dissolved o2 is gone.
 

gregbathurst

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Sulfite is always helpful in this situation. It is always good to keep headspace to a minimum, also keep the cider on lees because the lees will use up excess O2. If you can't smell the vinegar it probably isn't very bad. You can also get acetic acid produced by lactobacillus from tiny amounts of residual sugar without oxygen, though that is less common. If you keg it, there will be a release of acetic acid odour when it is poured, if you let it sit for a minute it may dissipate.
 

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