Reference point
Light an incense stick, stand a metre away and smell the smoke.
Do this before you read on. An entry only works when you have just smelled the thing.
Sweet smoke, with a woody note and a faint powdery layer. Quite different from the smell of an unlit stick, which is little more than glue and sawdust.
This entry shows that fire does not just release smell but creates it. Most of what you smell did not exist before the stick was lit.
Agarwood incense, cassia incense and chemical incense give three very different results, and telling them apart is a real skill.
How to smell it
Stand a metre away, downwind. Don’t smell right at the tip of the stick — there the heat is high and the smoke dense, and everything merges. Smell again after the stick has burned out, when the light smoke has gone and only what clings to fabric remains.
Why this one is hard
Because it is tied so tightly to memory and to places of worship. For many people it is almost impossible to smell incense neutrally — emotion arrives before any description can form.
Don’t confuse with
This entry
Burning incense
Woody & Resinous family
Incense smoulders without a flame, so its smell is created in the pyrolysis zone behind the ember, giving many sweet phenols. Straw smoke burns in the open, hotter and more completely oxidised, so it is drier and less sweet.
Scientific note
Incense does not burn with a flame but smoulders, and notably there are two heat zones, not one. The glowing ember at the tip is very hot — measured values reported range from a few hundred degrees to over six hundred, a fairly wide spread depending on the stick’s composition and how it was measured. But the aromatics do not evaporate there.
The smell is born in the zone just behind the ember, where the heat is enough to break things down but not enough to burn them completely. In that temperature band, the lignin in the wood powder breaks down into guaiacol and other phenols, while any aromatic resins evaporate almost intact. If the tip bursts into a real flame, most of those compounds are burned off — which is why people blow out the flame after lighting.
Cheap incense uses synthetic fragrance soaked into sawdust, and it burns into quite different compounds.
In Vietnamese life
Incense is a smell present in every Vietnamese home on the full-moon and new-moon days of the lunar month. It is also one of the few smells whose intensity is adjusted to the occasion: three sticks on an ordinary day, a whole bundle on a death anniversary.