My vinegar smells like acetone (nail polish remover)!

Reginald SmithAll About Vinegar, Making Vinegar4 Comments

If you make vinegar long enough you have to tackle almost every problem. I sometimes get emails and questions about an “acetone” smell from vinegar, very similar to nail polish remover. What does this mean?

First, you must understand the process by which acetic acid bacteria turn alcohol into vinegar. The short chemical pathway is:

Alcohol (Ethanol) + Oxygen -> Acetaldehyde + Oxygen -> Acetic Acid + Water

The middle step is rarely discussed because it isn’t of use to the average vinegar maker. Acetaldehyde is an intermediate step on the way from alcohol to vinegar. And if you get my drift, acetaldehyde in concentration smells a lot like acetone.

So the acetone smell is what happens when the reaction to make vinegar isn’t completely finished. Many bacteria just make acetaldehyde and then start creating the pungent odor. The reasons for incomplete reactions can vary but the top two are lack of air (oxygen) and too much alcohol in the starting mash.

Vinegar fermentation requires oxygen and needs a plentiful supply. That’s why a porous (but not porous enough for fruit flies) cloth like cheesecloth is all you want closing up your jar or barrel. Having enough air usually prevents the issues with stalled fermentation.

The other reason is too much alcohol in your starting mash. As has been stated the starting mash should not have an alcohol content exceeding 10% ABV. I would not go higher than 8% ABV if you are using traditional methods. Too high an alcohol content puts stress on the bacteria. They spend too much energy trying to cope with the poisonous effects of high alcohol concentration and don’t have the resources to ferment vinegar correctly, leaving a lot of acetaldehyde. The solution to this is lowering the alcohol content.

Another thing you can do is put a packet of brewer or baker’s yeast for up to 5 gallons of vinegar to provide nutrients to help fermentation.

4 Comments on “My vinegar smells like acetone (nail polish remover)!”

  1. Sharon A Lorentzen

    I make my acv with about 3 1/2 quarts of chopped apples, a cup of organic sugar in a gallon jar and fill to the shoulders with filtered water. No added alcohol or yeast. Cover the jar with a coffee filter secured with elastic, and stir1-2 times daily. It is now 6 weeks old and smells like acetone. Do I understand correctly that the acetone smell will not last as fermentation progresses and I do NOT have to throw it out?

    1. Reginald Smith

      You should not have to throw it out. Once the bubbling stops (meaning the end of alcohol fermentation) you no longer need to or should stir it since you need a mother to form. A lack of a mother can limit oxygen absorption and may be the reason for the acetone smell. I say let it stand for a few weeks and it should get better. If not, add a little bit of yeast (1 gram or less) to give it some extra nutrients.

  2. Jim

    I started a batch of red wine vinegar for the first time about 4 weeks ago. I added about 1 gallon of Red wine and 2 bottles of red wine vinegar with mother. I covered it with cheesecloth for 2-3 weeks and afterwards placed a lid on it. It now smells like nail polish remover and it seems to sweat inside the jar. Reading your post, I made 2 mistakes. 1. I did not reduce the alc content and 2. Did I destroy it by covering it after 3 weeks?
    Can I now dilute it and maybe expose it to some air and it will turn out ok? Worried about mold etc.

    1. Reginald Smith

      Hi, you should not have covered it with a lid but kept on the cheesecloth until the vinegar is done. However, you have not destroyed or ruined it. You should also make sure you cut the wine at least 1:1 wine to water+mother. If the bottles of red wine vinegar with mother were 16 oz I am guessing, add one quart of water and that should bring the alcohol more in line. If you remove the lid and put the cheesecloth back on the fermentation should resume and the acetone smell should disappear.

      If you are worried about mold, instead of a quart of water add a quart of vinegar (red wine or white distilled) so the acidity is low enough to ensure no mold growth. Mold isn’t a huge problem with red wine mother typically unless the wine itself was heavily contaminated with spores (this happens though it doesn’t cause any health problems with people).

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