Comparison
Volatile acidity vs ethyl acetate
What is the difference between volatile acidity and ethyl acetate in cider?
In short
Volatile acidity in cider is overwhelmingly acetic acid, produced when acetic acid bacteria oxidise ethanol in the presence of oxygen. It presents as a vinegar smell and a sharp sourness on the palate.
Ethyl acetate is the ester formed from acetic acid and ethanol. It smells of solvent, nail varnish and pear drops, and its sensory threshold is much lower than that of acetic acid — so a cider can smell of solvent well before it tastes of vinegar.
They usually appear together, because the same bacterial activity that raises acetic acid provides the substrate for the ester. Small amounts of ethyl acetate arise from ordinary fermentation and are part of normal cider aroma; a rising level alongside vinegar character is a different signal, and it means the cider is still deteriorating.
The two things being compared
Each side described in its own terms first, so the table below has something to hang on.
Volatile acidity
Acetic acid produced by acetic acid bacteria oxidising ethanol. Presents as vinegar on the nose and sharp sourness on the palate.
Ethyl acetate
The ester of acetic acid and ethanol. Smells of solvent, nail varnish and pear drops, at a much lower threshold than acetic acid itself.
Where they differ
Dimension by dimension. Where a row needs a qualification, it carries one rather than being simplified until it fits.
| Dimension | Volatile acidity | Ethyl acetate |
|---|---|---|
| Compound | Acetic acid. | Ethyl acetate. |
| Aroma | Vinegar. | Solvent, nail varnish, pear drops. |
| Taste | Sharp and sour on the palate. | Chiefly an aroma; contributes little sourness. |
| Sensory threshold | Higher. | Much lower, so it is usually detected first. |
| Origin | Acetic acid bacteria with oxygen; also lactic bacteria in some circumstances. | Esterification of acetic acid with ethanol, and in small amounts from ordinary yeast metabolism. |
| Normal at low levelNeither compound is abnormal in itself. Both are faults at concentration and when rising. | A small amount is present in every cider. | Also present, and part of normal fruit-ester aroma. |
| What it signals | Oxygen exposure and a bacterial population. | The same, usually a step further on. |
| Remedy | Prevention — full vessels, hygiene, sulphite. Once high, blending is the only partial option. | The same; the ester cannot be removed at scale. |
Notes under a dimension name qualify the whole row, not one column.
When Volatile acidity is the relevant one
The circumstances in which this is the thing being described, rather than a reason to prefer it.
- The cider smells and tastes of vinegar.
- You are quantifying the fault, since volatile acidity is what is measured.
When Ethyl acetate is the relevant one
The circumstances in which this is the thing being described, rather than a reason to prefer it.
- The cider smells of solvent or nail varnish rather than of vinegar.
- You are explaining why a fault is detectable on the nose before the palate.
A misconception worth clearing up
This comparison exists partly because of the claim below, which is repeated often enough that most readers arrive holding it.
Volatile acidity and ethyl acetate are two names for the same fault.
What is actually the case: They are distinct compounds. Volatile acidity is what is measured and reported analytically; ethyl acetate is a separate ester with a far lower threshold, which is why a cider can be flagged as solventy on the nose while its measured volatile acidity is still unremarkable.
Related comparisons
Distinctions that turn on the same thing, or that this one is routinely confused with.
Cider vs cider vinegar
Cider vinegar is made from cider by a second, bacterial fermentation that oxidises ethanol to acetic acid — a deliberate industrial process, not simply what cider turns into if left alone.
Oxidation as fault vs oxidation as style
Controlled slow oxidation during maturation develops colour, softens tannin and adds complexity; uncontrolled oxidation strips fruit aroma, browns the cider and pushes it towards acetaldehyde and vinegar.
Fault vs style feature
Many of the compounds recorded as faults are present in well-regarded traditional ciders. What separates a fault from a feature is concentration, integration and whether the producer intended and controlled it.
What people ask next
Questions readers ask about the things this page mentions. Each one goes to the section that answers it rather than to a page written to receive the question.
- When is a cider faulty and when is it just traditional — The same compound can be either, and the deciding factor is the tradition the cider belongs to and the concentration. Volatile acidity that would condemn a modern fresh-fruit cider is expected in a traditional Asturian one, and neither judgement is wrong.
- Is cider vinegar just cider that has gone off
- When is oxidation in cider a fault
Where to go next
- All comparisons — The rest of the pairs, grouped by what kind of difference is at stake.
- Glossary — Either term on its own, defined without a second thing to hold it against.
- Learn about cider — The background these pages assume, written from the beginning.
Sources
What this page rests on. Where a source is marked as registered rather than read, CiderHQ is recording that the body is authoritative on the subject without claiming to have worked through the document itself. See our evidence policy for what each state means.
The Science of Cidermaking and associated technical writing
Andrew Lea · reference work · passage verified 2026-08-24
Written by a food chemist who worked at Long Ashton on apple phenolics. Unusual among specialist cider writing in that it is primary-research-adjacent: the author is describing work he did, and cites the literature. This is why it is registered at tier 1 for chemistry while a general cider book is not.
Peer-reviewed literature on cider fermentation microbiology
Various journals · peer-reviewed literature · registered as competent for this subject
Covers the microbial succession of spontaneous cider fermentation, the role of non-Saccharomyces yeasts in the early stages, malolactic conversion by Oenococcus and Lactobacillus species, and the organisms behind the principal spoilage faults.
Cider and perry production technical training material
Peter Mitchell / Cider and Perry Academy · reference work · registered as competent for this subject
Searched again on 2026-08-25 and it remains the one printed source here that a bibliographic check cannot fix, because it is not a published work with an edition. It is course material issued to participants of a training programme, so there is no catalogue record to verify, no ISBN, and no lawful public copy. Its state stays `registered` for that reason rather than through inattention.