Material guide: benzaldehyde — 108 suppliers, four hours' longevity, and it shares a reaction with hydrogen cyanide

The database's synonym field for this one reads: artificial bitter almond oil.

And its numbers read like this:

Suppliers	108
Longevity	4 hours at 100%
Vapour pressure	1.270 mmHg @ 25 °C

A hundred and eight suppliers, four hours.

The last article worked out that 15.6% of materials with a longevity record last under eight hours, and that this band has the highest mean supplier count of all five. Benzaldehyde is the clearest case in it: an odour almost everyone recognises, a material available everywhere, four hours.

The short version

• 108 suppliers, 4 hours' longevity. It is the most direct counterexample to "short-lasting means second-rate".
• Its GHS carries H334: may cause allergy or asthma symptoms or breathing difficulties if inhaled. Of the 369 database records carrying GHS data, only 4 include that statement.
• Shelf life is 18 months — of the 1,303 records with a shelf life, only 21 say 18 months, with most saying 24 or longer. And the storage field says store under nitrogen.
• Its concentration in white bread is 40,903 ppm (about 4.1%), two orders of magnitude above many fruit juices. That is a Maillard product, not something the fruit brought.
• A 2026 study confirms that in bitter almond, the almond smell and the hydrogen cyanide come from degradation of the same precursor. Heat processing does both at once: it makes the smell and it detoxifies.

The basics

Also known as	Artificial bitter almond oil
CAS	100-52-7
Formula	C₇H₆O
Molecular weight	106.12
Type	Natural/synthetic
Odour	Sharp, sweet, bitter, almond, cherry, fruity, powdery, nutty, maraschino cherry
Odour family	fruity
Strength	High (evaluate at 10% or below)
Longevity	4 hours at 100% (a neat value)
Appearance	Colourless to pale yellow clear liquid
Boiling point	178–179 °C @ 760 mmHg
Melting point	−26 to −25 °C
Flash point	62.8 °C
Vapour pressure	1.270 mmHg @ 25 °C
logP	1.50 (est)
Water solubility	6,570 mg/L @ 25 °C
Storage	18 months; cool, dry, sealed, away from heat and light, under nitrogen
Regulatory	JECFA, FEMA GRAS, CoE, FLAVIS
Suppliers	108
Corpus position	28 formulas, median dose 0.50% (range 0.01–50.00%, appearing as a pre-dilution in 10 of the 28)

That rare GHS statement

Most materials' GHS fields list skin irritation, eye irritation and aquatic toxicity. This one adds something uncommon:

H227	Combustible liquid
H302 + H332	Harmful if swallowed or if inhaled
H315	Causes skin irritation
H317	May cause an allergic skin reaction
H334	May cause allergy or asthma symptoms or breathing difficulties if inhaled
H401	Toxic to aquatic life

H334 is respiratory sensitisation. I counted: of 42,225 material records, 369 carry GHS data, and only 4 of those include H334.

It is not the same thing as H317, skin sensitisation. H317 is about contact with skin; H334 is about inhalation. And most of the exposure at a perfumer's bench happens by inhalation.

In practice: ventilate when you open and dilute it, and do not put your nose over the neck of the bottle and inhale deeply. That applies to every material, and applies with particular force here.

(The usual caveat: GHS coverage is 369 of 42,225, so "another material has no such statement" usually means that material has no data.)

Eighteen months and nitrogen

Shelf life 18 months. That is uncommon in the database — of the 1,303 records carrying a shelf life, only 21 say 18 months, with most saying 24 or longer.

And beyond cool, dry, sealed and away from light, the storage field says store under nitrogen. That phrase appeared in the last material guide, helional, where I counted it in 92 of 1,232 records with storage advice.

Both facts point at one cause: it is an aromatic aldehyde, and aromatic aldehydes oxidise to the corresponding acid. Benzaldehyde's oxidation product is benzoic acid, which is a solid at room temperature — so an old bottle develops crystals or a deposit. That is not contamination; that is the material turning into something else.

This is one of the few materials whose ageing you can see with your eyes.

Handling is the same as for other aldehydes, and storage and oxidation has the full procedure: decant into small bottles, open the large one rarely, make stock solutions in small batches. The only difference here is a shorter clock.

Four percent of white bread

The natural occurrence field runs long, and one figure in it is worth stopping on:

Source	Concentration
White bread	40,903 ppm
Apple juice	294 ppm
Beer	216 ppm
Apple	47 ppm
Butter	1 ppm
Cassia bark oil (China)	0.54%
Cassie absolute	5.98%

Forty thousand nine hundred and three ppm is about 4.1%. That is more than two orders of magnitude above apple juice.

The benzaldehyde in bread did not come from fruit; it was baked. It is one of the products of the Maillard reaction and related thermal chemistry. So the "almond" association is chemically broader than it is botanically — one molecule explains bitter almond, cherry stones, and one facet of bread crust at the same time.

Incidentally the odour field reads "sharp, sweet, bitter, almond, cherry, fruity, powdery, nutty, maraschino cherry". That last descriptor is exact — it is how this molecule is most recognisably encountered in food.

The almond smell and the hydrogen cyanide, one reaction

This is the chemistry most worth knowing about this material.

Zhao and colleagues, in ACS Omega in 2026, profiled the metabolites of bitter almond. Their opening is blunt: as a traditional Chinese medicine, bitter almonds contain amygdalin, which can be hydrolysed by β-glucosidase to release highly toxic hydrogen cyanide. There are safety hazards in clinical use, and high-temperature pretreatment is required.

They used SPME-GC-MS and UPLC-MS/MS to compare metabolic profiles before and after different pretreatments (steaming, boiling, frying). Volatile analysis identified 30 compounds, with terpenoids such as d-limonene and linalool significantly upregulated during steaming while benzyl alcohol was significantly downregulated. Non-volatile analysis identified 199 metabolites, of which 80 differed significantly — steaming downregulated 45 substances against 19 for boiling and 23 for frying, a clear trend of degradation.

And the key sentence: during processing, the cyanogenic compound prunasin degrades significantly, forming volatile products including benzaldehyde and hydrogen cyanide, which confirms the detoxification mechanism of processing at the molecular level.

One precursor, giving the smell and the poison together.

What this means for your bench needs stating plainly: the benzaldehyde you buy did not come from there. Commercial benzaldehyde is synthesised, or isolated from sources such as cassia oil. It is benzaldehyde; it carries no cyanogenic glycoside. This chemistry explains why almond and danger are culturally bound together — it is not a statement that what is in your bottle is toxic.

What actually warrants attention is the H334 above, and the flash point of 62.8 °C — low for this series (cyclamen aldehyde 109 °C, helional above 93 °C) — so store it as a flammable liquid.

Its day job in plants

Xing and colleagues, in Microbiology Spectrum in 2023, studied the volatile organic compounds produced by a fungus (Ceratocystis fimbriata) as potential biocontrol for postharvest disease in cherry tomato.

A double Petri dish assay showed those volatiles inhibited mycelial growth of Alternaria alternata by 52.2% and 42.9%. GC-MS identified 42 single volatile components, from which four with antifungal effect were screened: benzaldehyde, nonanal, 2-phenylethanol and isoamyl acetate. The lowest IC50 values belonged to benzaldehyde and nonanal (0.11 and 0.04 μL mL⁻¹). Pathogens exposed to the volatiles showed abnormal hyphal morphology, delayed sporulation and inhibited spore germination; in vivo, all four suppressed disease incidence on inoculated fruit, with the two aldehydes more prominent at delaying onset.

This paper is here because it explains why the molecule is so widely distributed in nature: it is a defensive volatile. The benzaldehyde in fruit, seeds and bark is not there to smell nice.

This is postharvest biocontrol research, not a health claim, and it says nothing about what happens when you put it on skin.

Smelling it and using it

• Start at 0.5%. That is the corpus median, and 10 of its 28 appearances are as a pre-dilution. The strength field says high, evaluate at 10% or below.
• The range runs 0.01% to 50%. The top end is almond and cherry formulas built around it. Three orders of magnitude between median and maximum is unusual in this corpus.
• It leaves. Four hours, 1.27 mmHg. Its job is the opening and that instant of recognition, not the back half.
• Note the word "bitter". It is the third descriptor in the odour field. At higher concentrations it turns from almond into a sharp bitterness, and that is where it is easy to overdo.
• It is quite water-soluble at 6,570 mg/L. Against the starter palette's median of 100 mg/L, that is 65 times higher. In a product containing water, it will move into the water phase.

Buying and storage

A hundred and eight suppliers, very easy to get. Buy on CAS 100-52-7.

Buy small. Shelf life is 18 months and it oxidises. Buying a kilo and keeping it three years produces a bottle of benzoic acid crystals.

Flash point 62.8 °C: store it as a flammable liquid, away from heat.

Regulatory and safety

Six GHS statements as above, of which H334 is respiratory sensitisation — a rare entry in this database. Ventilate when opening and diluting.

Acute toxicity figures are scattered: gavage guinea pig LD50 1,000 mg/kg, gavage rat 1,300 mg/kg, and a separate oral rat figure of 2,850 mg/kg. Numbers from different eras and species support a direction, not a ratio.

Flavour listings are comprehensive (JECFA, FEMA GRAS, CoE, FLAVIS). Check current IFRA Standards for the limit — here is how. It carries both H317 and H334, so that step is not optional.

→ Benzaldehyde in the database: full physical data, 108 suppliers and suggested blends. → Search by odour: try "almond cherry sweet".

References

L. Zhao, J. Ma, F. Hao, X. Li, Q. Feng, Unraveling the Impacts of Preprocessing on the Metabolite Profile of Bitter Almond Using UPLC-MS/MS and GC-MS Analysis, ACS Omega, 11(25), 37619–37630 (2026). PMID 42396009. doi:10.1021/acsomega.6c02445

S. Xing et al., Antifungal Activity of Volatile Components from Ceratocystis fimbriata and Its Potential Biocontrol Mechanism on Alternaria alternata in Postharvest Cherry Tomato Fruit, Microbiology Spectrum, 11(1), e0271322 (2023). PMID 36625661. doi:10.1128/spectrum.02713-22