Cinnamaldehyde
Also written trans-cinnamaldehyde, cinnamic aldehyde, cinnamaldehyde (trans)
Quick answer
The compound that smells of cinnamon, and the great majority of what is in cinnamon bark oil — which is why the two cinnamons taste alike and differ in almost everything else.
What it does
Cinnamaldehyde is the warm, sweet, faintly woody smell that the word cinnamon denotes. It also has a mild pungency of its own, felt as a warming prickle rather than a burn, which is why strong cinnamon reads as hot in a way that no purely aromatic spice does. It dominates the oil of both cassia and true cinnamon so completely that the family resemblance is unmistakable; what separates them is everything else — cassia is nearly all cinnamaldehyde and reads as blunt and forceful, while Ceylon cinnamon carries a substantial fraction of eugenol and other aromatics alongside it and reads as more complex, more floral and less brutal.
How it behaves when cooked
Four properties of the molecule, and what they mean at the stove.
- Volatility
- moderate
- Fat solubility
- high
- Water solubility
- low
- Heat stability
- moderate
Cinnamaldehyde is soluble enough in fat and just soluble enough in hot water to make both extraction routes work, which is why cinnamon is one of the few spices equally at home in a butter-and-sugar bake and in a simmered liquid. A quill in a braise, a rice pot or a mulled drink gives up its cinnamaldehyde slowly over the whole cooking time and can then be removed, which is the reason whole cinnamon suits long wet cooking where ground cinnamon would go gritty and muddy the texture without tasting stronger. Sustained high heat drives it off and oxidises it, so cinnamon added at the start of a long open simmer is noticeably weaker at the end; in a closed pot, where nothing escapes, it is not. In baking it is protected inside the crumb and survives well, which is why the traditional cinnamon applications are exactly the two extremes — enclosed in a dough, or infused in a liquid and retrieved.
Spices that carry it
Recorded on the compound rather than on each spice, so the two cannot disagree.
- CassiaPrincipal component
Overwhelmingly the dominant compound, which is why cassia tastes powerfully of cinnamon and of little else.
- Cinnamon (Ceylon)Principal component
Principal, but sharing the field with eugenol and a wider aromatic fraction — the chemical basis of the difference readers taste between the two barks.
- IshpingoMajor component
About a third of the flower-cup oil, sharing the stage with methyl cinnamate, which is what makes ishpingo sweeter than cinnamon.
- Tej pattaMajor component
The leading compound among five measured by HPLC in 28 leaf samples from the Western Himalaya, at 0.39–1.27 per cent of the dried leaf; a leaf oil distilled from Bangladeshi market leaves held 16 per cent.
- MahlebContributing component
Second among the aldehydes in the headspace of raw mahlab seed from Greece and Egypt, at about 7 to 12 per cent of the volatiles, behind benzaldehyde; roasting cut it to about 2 per cent.
What cooking and processing were measured to do to it
Findings from studies in which this compound was followed through heat, fat, water, drying or storage. Each belongs to its study and its conditions.
Simmering and boiling · Depends on conditions Cinnamaldehyde, Coumarin, Cinnamic acid, Cinnamyl alcohol, 2-Hydroxycinnamaldehyde
What hot water draws out of cassia bark shifts with the temperature and the time. Between 70 and 95 °C and between 2 and 12 min, hotter and longer extraction raised the coumarin and cinnamyl alcohol content of the extract and lowered its content of cinnamaldehyde, cinnamic acid and 2-hydroxycinnamaldehyde.
Conditions: in water · 70, 75, 80, 85, 90 and 95 °C · 2 to 12 min · Microwave-assisted extraction of Cinnamomum cassia bark with water
A long, hot infusion of cassia is not simply a stronger version of a short one. In this study it held less of the compound that smells of cinnamon and more coumarin.
What this does not show: Read in the abstract only, which gives directions and significance but no concentrations. Microwave-assisted laboratory extraction, and cassia only; it does not speak for Ceylon cinnamon, and it does not say whether the cinnamaldehyde was lost as vapour or chemically changed.
Measured on the spice
Toasting and dry roasting · Depends on conditions Cinnamaldehyde, benzaldehyde, γ-caprolactone, isomintlactone, γ-nonalactone
Roasting shifted the headspace of red Egyptian mahlab from aldehydes to lactones. Lactones rose from 6.8 to 24.2 per cent of the volatiles, with γ-caprolactone climbing from 2.14 to 6.58 per cent, isomintlactone from 1.19 to 8.31 and γ-nonalactone from 0.88 to 4.20. Benzaldehyde and (E)-cinnamaldehyde, the leading aldehydes of the raw seed, fell to 0.8 and 1.9 per cent. The authors link the lactone rise to the brief heating with which mahlab is traditionally used in confectionery.
Conditions: in air · 180 °C on a heating mantle · 15 to 20 min · Powdered seed, 5 g wrapped in aluminium foil; red mahlab from Egypt compared raw and roasted
What this does not show: Relative peak areas from headspace sampling, not concentrations, on a few seed lots; the odour notes attached to the lactones come from the literature and no sensory test was made of the roasted seed.
Measured on the spice
Not to be confused with
Compounds a reader is likely to take for this one, and why they differ.
Coumarin
The compound cassia is restricted for is coumarin, not cinnamaldehyde. They are different molecules with different consequences, and the widespread shorthand that "cinnamon is limited" collapses a rule about one into a warning about the other.
Questions this page answers
- what is cinnamaldehyde
- what does cinnamaldehyde do
- which spices contain cinnamaldehyde
- what is trans-cinnamaldehyde
- what is cinnamic aldehyde