Say that I have a wine that still contains a substantial amount of sugar. If I start the process of converting the wine to vinegar by exposing it to oxygen, will the sugar continue to be converted to alcohol during this process? Or will the sugar remain even as the wine is converted to vinegar?

  • Depends on to many factors. How fermentation stopped? Are there yeast in your wine or they were killed using sulphur? If sulphur, is it compound that will get away into the air? Are there wild yeast or fermentation bacteria in your air? And so on.
    – Mołot
    Jan 24, 2016 at 23:44
  • More specificly, I have made apple wine the natural way without any added yeasts on my part. I exposed the wine to the air before all the sugar had been used up. It still tasted sweet and apply and smelled of apple juice as well as ferment. I let this become vinegar, again with no added substances. An entirely natural process. I felt the vingegar was good but wondered if the sugar was consumed by the vinegration process. Brewchez confirmed that it did.
    – Amoxus
    Jan 25, 2016 at 14:18
  • Please edit question to add data.
    – Mołot
    Jan 25, 2016 at 14:22

2 Answers 2


Simply exposing a wine that was inoculated with wine yeast to oxygen doesn't create acetic acid. You need to inoculate with some acetic acid bacteria as well.

Acetic acid bacteria can ferment both sugars and ethanol to make acetic acid.

I have made red wine before, and I have pulled a gallon of partially fermented wine, inoculated with acetobacter and gotten a decent product.

With a fully fermented wine, it will take more time for the acetobacter to convert just the ethanol to acid. Seeing as you still have some sugar, I'd pitch some acetobacter and let it go from there. Consult your local brew shop for the appropriate bacterial strain.


Vinegar is a result from acetobacter infection. Just leaving it open may not inoculate the wine with it.

If fermentation was suspended by potassium metabisulfide or the like you may be able to oxygenat and repitch yeast to have all the sugars fermented before attempting to convert to vinegar.

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