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.
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