Material guide · 79
Material guide: octyl acetate — one record describes it as jasmine and as mushroom
· 22 min read
CAS 112-14-1. Fifty-five suppliers. Its odour type field says floral, while its odour field reads green, earthy, mushroom, herbal, waxy, fruity, apple. Within that same record, one supplier's note says "Odor: Jasmine", another says floral, herbaceous, fruity, and the database's own description is green, earthy, mushroom, herbal, waxy. This is not a data error; it is what this molecule is like. It is simultaneously a trace natural constituent of bergamot oil (0.07-0.20%), a major constituent of Boswellia occulta frankincense, and a synthetic adulterant that a 2022 study found in commercial frankincense oils.
This series has read a lot of odour fields. What is unusual here is that this record disagrees with itself.
The database's fields:
| Field | Content |
|---|---|
| Odour type | floral |
| Odour | green, earthy, mushroom, herbal, waxy, fruity, apple |
The type says floral and the description says mushroom.
And the suppliers' notes collected in that same record give two more:
Advanced Biotech, OCTYL ACETATE NATURAL: "Odor: Jasmine" Alfrebro, n-OCTYL ACETATE NATURAL: "Floral, Herbaceous, Fruity" The database's own description (Luebke, 1982): "green earthy mushroom herbal waxy"
Three sources, three directions: jasmine; floral-herbaceous-fruity; green-earthy-mushroom.
The short version
- CAS 112-14-1, C₁₀H₂₀O₂, MW 172.27, 55 suppliers.
- The odour type is floral, while the odour field's first word is green and its third is mushroom.
- Three independent sources give three different descriptions, one of them simply "Jasmine".
- Substantivity 16 hours at 100%, strength medium, shelf life 24 months.
- Its place in nature is scattered: apple, apple juice, beer, bergamot oil @ 0.071-0.199%, blood orange oil…
- And outside perfumery it has a more conspicuous identity. A 2022 study analysing 21 commercial frankincense oils found synthetic octyl acetate in 3 of them, plus one more as part of a compound adulteration; and 2 samples contaminated with Boswellia occulta, a species naturally rich in this molecule.
- GHS carries two lines: H226 flammable and H303 may be harmful if swallowed.
About 8 minutes.
Three descriptions, one molecule
To be clear: this is not the database making a mistake.
We've written about database fields being wrong (veramoss's occurrence field) and incomplete (dihydro-β-ionone missing osmanthus). This record is neither. All three descriptions may be correct.
Olofsson and Gottfried open their 2015 paper in Trends in Cognitive Sciences with this:
Most people find it profoundly difficult to name familiar smells.
Their point is that this difficulty persists even when perceptual odour processing and visual object naming are unimpaired, meaning the problem sits between the senses and the language system. They split it across three successive stages: object perception, lexical-semantic integration, and verbalisation.
We used the same paper in the forty-materials piece — there, four people described one Oceanol four ways. This time three descriptions sit inside a single database record.
And there is a structural reason this molecule shows the effect so clearly.
Why it does this
Octyl acetate is the acetate ester of a straight-chain C8 alcohol.
Straight-chain fatty esters have a characteristic: they carry both a fruity-ester character and a fatty-waxy one, and which dominates depends on concentration, purity and your nose.
- At low concentration, against a fruity background, it reads as apple, fruity, floral — hence "jasmine".
- Neat and at high concentration, the C8 chain's fatty quality comes forward, with a mushroom-like earthiness alongside — hence "green, earthy, mushroom".
Both descriptions are of one material seen from two conditions.
(To be clear: that explanation is my general statement about this class of molecule, not something from the cited papers. The database does not say at what concentration those three descriptions were made, though Luebke's is marked "at 100.00%" — neat. The other two carry no concentration.)
The practical upshot is direct: if a bottle you bought does not smell like what you read, first check whether you were both smelling it at the same concentration. The same lesson as the orris butter piece.
Where it sits in nature
The occurrence field is scattered:
apple, apple juice, beer, bergamot oil @ 0.071-0.199%, bergamot oil @ 0.15%, bergamot oil Turkey @ 0.09%, blood orange oil (Sanguinello, Italy) @ 0.007%, blood orange oil (Tarocco, Italy)…
Note the bergamot lines. Same oil, different sources, from 0.071% to 0.199% — close to a threefold range. We've written about batch variation, and this is what it looks like for a trace constituent.
It is a trace constituent in citrus oils and a natural constituent of apple and beer.
And in frankincense it can be a major one.
The frankincense story
This is what is most worth knowing about the material outside perfumery.
Boswellia occulta is a comparatively recently described frankincense species, and it is naturally rich in octyl acetate. Its essential oil therefore has a greener, sharper top than frankincense generally.
And Ojha and colleagues' 2022 study in Plants puts that into a more complicated context.
They used GC-MS and chiral GC-MS on 21 commercial and 2 lab-distilled frankincense (Boswellia carteri) essential oils. Among those 21:
- 3 were contaminated with synthetic octyl acetate
- 1 more was a compound case of "copaiba resin + frankincense resin + synthetic octyl acetate"
- 2 were contaminated with Boswellia occulta species
So one molecule, appearing in a bottle labelled B. carteri, can mean two entirely different things:
| Source | Meaning |
|---|---|
| Natural, from B. occulta | species mislabelling or blending |
| Synthetic, added | adulteration |
And both smell like "this frankincense is greener and sharper than expected".
Which is also why that paper used chiral GC-MS. Chiral analysis looks at enantiomeric distribution — natural and synthetic sources usually differ there, and it is one of the few tools that can separate them.
(Octyl acetate is itself achiral, so the paper's chiral analysis targeted other terpenoids in the samples. I mention the method to describe the paper, not to claim it was used on this molecule.)
The full context is in the companion piece. What to keep here: if a frankincense you bought is greener than you expected, this molecule is the first suspect, and it has two routes in.
Physical properties
| Property | Value |
|---|---|
| CAS | 112-14-1 |
| Formula | C₁₀H₂₀O₂, MW 172.27 |
| Appearance | colourless clear liquid (est) |
| Boiling point | 206-211 °C |
| Melting point | −38 to −37 °C |
| Flash point | 81.7 °C |
| logP | 3.40 (est) |
| Water solubility | 33.39 mg/L at 25 °C (est) |
| Substantivity | 16 hours at 100% |
| Strength | medium |
| Shelf life | 24 months or longer |
| Suppliers | 55 |
| Regulatory listings | JECFA, FEMA GRAS, CoE, FLAVIS |
| GHS | H226 flammable liquid and vapour, H303 may be harmful if swallowed |
Sixteen hours puts it in the shorter part of the middle for this series — longer than cis-3-hexenyl acetate's under 4, longer than dihydro-β-ionone's 9, and a long way from isoeugenol's 400.
Two GHS lines, both mild. No sensitisation and no aquatic hazard.
A 24-month shelf life. It is an ester and will hydrolyse — moisture is its enemy.
What this doesn't establish
I have not smelled it. The whole piece sets database fields against two papers.
"All three descriptions may be correct" is my interpretation, not a demonstrated claim. One of them may simply be wrong, and I cannot tell from the database.
"Straight-chain fatty esters carry both characters, and which dominates depends on concentration" is my general statement about this class, not drawn from either cited paper. I found no source for that passage.
Only one of the three descriptions carries a stated concentration (Luebke's "at 100.00%"). The other two do not, so the different-concentration explanation is itself unsupported by the data.
Olofsson's paper is a general review of naming difficulty, not a study of this molecule. I cite it to establish that multiple descriptions of one odour is a known phenomenon, not to explain where these three came from.
Ojha's study covered 21 particular commercial frankincense oils, not a random draw from the market, and the paper does not say how those 21 were chosen. "Synthetic octyl acetate is a common adulterant" is a stronger claim than that paper supports.
"B. occulta is naturally rich in octyl acetate" is my statement of background. Ojha's paper mentions B. occulta contamination, but the abstract does not give that species' octyl acetate content. I found no direct source for that sentence.
The bergamot range of 0.071-0.199% is a number in the database's occurrence field, with no primary source.
The GHS classification is what the database records, not a complete regulatory determination. Work from the SDS for your own batch and the current IFRA standard.
References
P. K. Ojha, D. K. Poudel, A. Rokaya, R. Satyal, W. N. Setzer, P. Satyal, Comparison of Volatile Constituents Present in Commercial and Lab-Distilled Frankincense (Boswellia carteri) Essential Oils for Authentication, Plants, 11(16), 2134 (2022). PMID 36015437. doi:10.3390/plants11162134
J. K. Olofsson, J. A. Gottfried, The muted sense: neurocognitive limitations of olfactory language, Trends in Cognitive Sciences, 19(6), 314-321 (2015). PMID 25979848. doi:10.1016/j.tics.2015.04.007
Related: my frankincense smells like sage, cis-3-hexenyl acetate, batch variation, the starter palette map.