I have been reading about using CH3COOH + H2O (vinegar) as a mild antibacterial and antiviral agent. For example: https://pubmed.ncbi.nlm.nih.gov/15698693/

Note, before anyone gets confused (or concerned), this has nothing to do with the SARS-CoV2 virus which causes COVID-19. I strongly doubt vinegar is effective at killing a coronavirus, and everything I have read confirms that doubt (the pH is too high, for starters).

Now, back to the topic at hand. Does CH3COOH + H2O lose its antibacterial and antiviral properties when exposed to room temperature air for a long duration (over 8 hours, but less than 500 hours)?

I've been trying to find scientific articles regarding this, and so far, have not found anything helpful.

Ideally, I would love to see one or more graphs that plot effectiveness along one axis and time duration of air exposure along the other. Of course, tables with data points would be equally welcome.

Note that I'm not looking for anything exact, as there are too many variables to be precise without getting into minute details. I'm looking for a general idea of the changes (if any) over time as CH3COOH + H2O is exposed to room temperature air.

  • $\begingroup$ Besides evaporating? $\endgroup$
    – Jon Custer
    Dec 10, 2020 at 14:25
  • $\begingroup$ @JonCuster Good question. Correct, besides evaporating. $\endgroup$ Dec 10, 2020 at 14:47
  • $\begingroup$ In what kind of setting do you want to use vinegar to kill what kind of bacteria or virus? Salad sauce? Yes, except that those pathogens that give you the shits can even survive the hydrochloric acid in your stomach. Otherwise, ... well, it's obvious. $\endgroup$
    – Karl
    Dec 10, 2020 at 20:23

1 Answer 1


Acetic acid boils at higher temperature than water, at 118 °C. Acetic acid does not react with the air.

It is more likely that acetic acid antimicrobial properties will improve as more water evaporates, because it evaporates faster.

  • $\begingroup$ Thank you for your answer. I think they key to your answer is the part where you wrote "Acetic acid does not react with the air". Assuming you are correct (and I have no data to the contrary), why does the smell of vinegar decrease the longer it sits exposed to air? As a simple test, you can pour 0.5 litre of common white vinegar into a wide bowl (to maximize surface area exposed to the air). After 1min, smell the air around it at a distance of 20cm. Repeat smelling the air after 1hr, then 12hr, then 24hr, then 48hr. When I did this, I noticed a significant decrease in the odor over time. $\endgroup$ Dec 12, 2020 at 3:27
  • $\begingroup$ If you are nearby this bowl, you will lose ability to smell this particular scent. Human body usually reduces percieved intensity of persistent stimulus, not just scents. You could test it by asking your friend to pour another bowl with new vinegar and let you try to distinguish it blindfolded, if im right you will not guess it better than 8\10. Another option is flavorings, if it is kitchen vinegar it may have something other than vinegar itself, and you sense that instead. $\endgroup$ Dec 12, 2020 at 3:33
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    $\begingroup$ Interesting thoughts... thank you. To reply, I am not regularly within 3m of the test bowl, so I don't think that's it. The blindfolded test you propose (is that a single-blind test? LOL!) is a great idea, and I may give that a try. Regarding flavorings, I will take a close look at the bottle, but the CH3COOH + H2O I tested was not cooking or cleaning vinegar. It should be nothing more than CH3COOH + H2O, but I need to confirm. $\endgroup$ Dec 12, 2020 at 3:43

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