Agarwood Resin Content: What It Means and How to Measure It

Resin content sits underneath almost every grading term covered elsewhere in this hub. Sinking rate, the Super and Double Super saturation labels, letter scales, all of them are, at root, different ways of describing the same underlying variable: how much aromatic resin a piece of agarwood holds relative to the plain wood, sometimes called whitewood, that surrounds it.

This guide covers the two main ways resin content actually gets measured, a quick density check anyone can run, and a formal laboratory standard used for commercial and medicinal grading, plus what each one does and doesn't tell you.

What "Resin Content" Actually Refers To

Agarwood resin is the aromatic compound mixture, predominantly sesquiterpenes and chromones as covered in our guide to how agarwood resin forms, that accumulates inside a tree's wood as a defensive response to wounding and fungal infection. "Resin content" describes what proportion of a given piece's mass or volume is this accumulated resin, as opposed to the underlying plain wood structure. A higher proportion generally means a denser piece, a stronger and more complex fragrance, and a higher market grade and price.

Density: The Quickest Resin Indicator

Density, or specific gravity, is the fastest practical way to estimate resin content, since resin is considerably denser than the surrounding wood and density rises roughly in proportion to how much resin a piece contains. Measuring it is straightforward in principle: weigh the piece, calculate its volume, commonly using water displacement for irregularly shaped chips or beads, and divide mass by volume.

Trade reference bands commonly cited for this method place mid-grade resin density between roughly 0.8 and 1.0 grams per cubic centimetre, with material above 1.0 grams per cubic centimetre, dense enough to sink in water, treated as the premium, top-tier range. One published measurement study found agarwood samples that floated entirely had densities between roughly 0.45 and 0.71 g/cm³, partially or fully submerged samples ranged between roughly 0.55 and 0.91 g/cm³, and fully sunk samples measured above 1.0 g/cm³, broadly consistent with these trade bands.

Sinking Rate Bands: First, Second, Third Grade

Within sinking material, the trade further grades by what percentage of a batch or piece actually sinks, covered in more general terms in our grading overview. A sinking rate of roughly 90 percent or higher is generally treated as top-tier, first-grade material; a rate between roughly 70 and 90 percent as second-grade; and a rate between roughly 50 and 70 percent as third-grade. These bands function as widely used trade reference points rather than a single codified international standard, and exact cutoffs can vary somewhat by seller and region.

Ethanol Extract Content: The Lab Standard

Beyond density, laboratories use a more rigorous chemical measurement: ethanol extract content, often abbreviated EEC%, which measures the actual mass of resin compounds that can be extracted from a dried sample using ethanol, expressed as a percentage of dry weight. The Chinese Pharmacopoeia, in its 2020 edition, sets a minimum EEC% of 10 percent by dry weight for agarwood to qualify as commercial or medicinal grade material, making it one of the few resin-content thresholds backed by a published, codified standard rather than trade convention alone.

EEC% and density measure related but distinct things. Density reflects the physical mass-to-volume ratio of a whole piece, including any voids or structural variation in the wood, while EEC% measures the actual chemically extractable resin content directly. A piece can show a particular density and a somewhat different EEC% result, since the two methods are capturing slightly different aspects of the same underlying resin accumulation.

Why Higher Density Often Means Different Chemistry

Resin content isn't just a question of how much resin is present, it also correlates with which specific compounds dominate. One study found that denser agarwood samples, above roughly 0.7 g/cm³, contained proportionally more chromone dimers, larger, more complex chromone molecules, while lower-density samples below that threshold contained proportionally more simple chromone monomers. This lines up with the resin chemistry covered in our resin formation guide: longer accumulation time appears to allow not just more resin to form, but more complex compounds to develop within it, which may help explain why aged, high-density material is so consistently associated with greater fragrance complexity.

What These Measurements Can't Tell You

Neither density nor EEC% confirms species, exact geographic origin, or whether a piece was wild-harvested or plantation-grown; those claims still rest on documentation and seller credibility, covered in our buying guide. Density measurements are also vulnerable to deliberate manipulation: wood injected with oil or resin under pressure specifically to mimic a high-density sink result, covered in our guide to fake oud, what to look for, can pass a basic sinking test without representing genuine, naturally accumulated resin. For high-value purchases, EEC% and full GC-MS chemical profiling remain the more reliable verification methods, since they're harder to fake than physical density alone.