Two vials of oud can differ in price by a factor of ten and carry labels that sound identical. Neither label is lying, exactly. There is no grading authority for oud — no appellation, no ISO number, no independent lab a buyer can appeal to. "Super A", "Grade 1" and "Double Super" mean whatever the house selling them has decided they mean, and the meaning changes at the next warehouse down the road.

What does not change is the material. If you know what actually creates value in agarwood, the labels stop mattering and the price starts making sense.

The resin is a wound response

Aquilaria trees are unremarkable. Healthy Aquilaria wood is pale, light and close to odourless; you could burn it and smell almost nothing. Oud exists only because the tree is injured and then infected, and floods the damaged tissue with a dark, dense resin to wall the infection off. That resin is the entire product. Everything around it is firewood.

This is why the first thing you pay for is time. A plantation tree inoculated four or five years ago has laid down a thin, pale seam of resin near the injection points. A wild tree that has been fighting the same infection for decades has resin running deep through the heartwood, heavy enough that the wood sinks in water. "Sinking grade" is one of the few honest descriptions in the trade, because it names a physical test anyone can run.

Where it grew, and which tree it was

Region is shorthand for species, climate and local distilling habit all at once.

  • Assam and the north-eastern belt, largely Aquilaria malaccensis, tends leathery and animalic with dried fruit underneath. It gives structure.
  • Cambodia and the Trat border area, largely Aquilaria crassna, tends sweeter and more resinous — the honeyed, faintly plummy profile most people recognise as oud.
  • Malaysian and Bornean material reads drier and woodier, sometimes with a cool green edge that surprises anyone expecting sweetness.
  • Papuan and Irian oils are sharper and more peppery, and are usually cheaper for reasons that have as much to do with how they were distilled as with the tree.

None of these are grades. They are accents. A carelessly distilled Cambodian is worse than a carefully distilled Papuan, and costs more.

The still does at least half the work

Traditional practice soaks the pounded wood in water for days or weeks before distillation. That fermentation is where the famous barnyard opening comes from — the note that makes a first-time buyer think the bottle has spoiled. It has not. A long-soaked oud opens with a farmyard blast and then resolves, over twenty minutes or so, into the wood underneath.

Short-soak and no-soak distillation give a cleaner, fruitier, more immediately likeable oil. That is not a lesser technique, it is a different one, and it is now the standard for oils aimed at people who would rather not spend the first half hour explaining their perfume.

Two further variables move the price quietly. Which pull you are buying: the first distillation carries the lightest and most complex fraction, and later pulls are heavier and flatter. And what the still is made of: copper, steel and clay do not produce the same oil from the same wood.

Why wild material is scarce and regulated

Aquilaria has been listed under CITES since the mid-1990s, with the whole genus covered from 2005. Legal wild material moves with permits, which is a real cost and a real bottleneck. Plantation agarwood exists precisely because the wild supply could not survive the demand — and a good plantation oil at a fair price is a better purchase than a "wild" claim nobody can verify.

What a buyer can actually check

You cannot verify a region from a bottle. You can check these.

  • Viscosity. Hold the vial sideways. Thin oil runs like water; resin-heavy oil hesitates against the glass.
  • The arc. Cheap oud is loudest in its first ten minutes and gone within the hour. Dense material opens quietly, gains for an hour, then holds close to the skin for most of a day.
  • Hours, not seconds. Judge on skin rather than a blotter, and give it four hours before you decide anything.
  • Price against plausibility. If a wild Cambodian costs less than the raw wood would, it is a reconstruction — synthetics and naturals built to give an impression of oud. That is a legitimate product, honestly sold. It becomes a problem only when the label does not say so.

The short version: you are paying for resin density, for the years it took to form, and for the care taken between the tree and the vial. The rest of what is printed on the label is vocabulary.