Agarwood resin content: what it means and how it is measured

Resin content sits beneath almost every grading term in this hub. Sinking grades, "super" labels and letter scales are all, at root, ways of describing how much aromatic resin a piece holds compared with the pale, unresinated wood around it, often called whitewood.

This guide covers the two main ways resin content is measured, a quick density estimate and a laboratory extraction, and what each can and cannot tell you.

What resin content means

Agarwood resin is the mixture of aromatic compounds, mainly sesquiterpenes and 2-(2-phenylethyl)chromones, that builds up in the wood as the tree responds to wounding and infection, as described in how agarwood resin forms. Resin content is the proportion of a piece made up of that material. More resin generally means a denser piece, a stronger scent when heated and a higher grade, though scent quality is not simply a function of quantity.

Density: the quick proxy

Resin is denser than wood, so density rises as resin builds up. To measure it, weigh a piece, find its volume, usually by water displacement for irregular chips, and divide mass by volume. Anything above about 1 g/cm³ sinks in water.

A 2026 study of Chinese agarwood gives a sense of the spread. Samples that floated had densities between roughly 0.45 and 0.71 g/cm³, samples that partly sank between roughly 0.55 and 0.91, and fully sinking samples were above 1.0, with the densest around 1.18. Sinking samples also had significantly more extractable resin than the other two groups, while floating and partly sinking samples were not clearly different from each other.

Ethanol extract content: the lab measure

Laboratories measure resin more directly as ethanol extract content: the mass of material that can be extracted from a dried, powdered sample using ethanol, expressed as a percentage of dry weight. It is one of the few resin measures backed by published standards.

The Chinese Pharmacopoeia (2020 edition) requires agarwood used as medicine, the resinous wood of Aquilaria sinensis, to contain not less than 10.0 percent alcohol-soluble extract and not less than 0.10 percent agarotetrol, a marker compound. Chinese forestry and local standards also use ethanol extract content, together with specific chromone compounds, as reference indices. These are standards for medicinal and Chinese commercial material, not a global trade rule.

Density and extract content measure related but different things. Density reflects the whole piece, including voids and structure, while extract content measures what can actually be pulled out chemically. A piece can score differently on each.

Density and chemistry

Resin content is not only about quantity. The same 2026 study found that samples denser than about 0.7 g/cm³ contained more chromone dimers, larger paired chromone molecules, while less dense samples contained more single chromone units. The authors suggest dimers may reflect a longer formation period and more advanced resin build-up, which could also help explain why dense, dark pieces are prized, though they present this as a hypothesis rather than a proven link.

What these measurements cannot tell you

Neither density nor extract content confirms species, origin, or whether wood was wild or cultivated. Those claims rest on documentation, covered in questions to ask before you buy oud. Density is also easy to distort: wood injected with oil or other material can sink without containing much natural resin, as described in fake oud: what to look for. Chemical tests are harder to fool, which is why they matter most for valuable pieces.