Have you tried to smell agarwood chips at room temperature? Typical answer per below:
If you were blindfolded, could you tell the differences between these 2? The one on the left is not so resinous wood, and on the right is a decent piece of agarwood chip
Some of you might say yes, so congratulation you had a good nose. However, it is not easy to identify these two without seeing them.
How about submerged these two chips underwater for 2 minutes and try blindfolded again just using your nose? Although we have not conducted this experiment, the number of people who could recognise the more resinous wood chip would be more than the first case (try to tell the difference between 2 without seeing the chips)
How about heating these chips? Could you identify the difference by experiencing the distinctive scent? One smell like campfire
The other, needless to say, earning its name as the "Wood Of God."
So, what makes the difference between these 2?
Takamatsu (2018), mentioned "Agarotetrol, a polar compound extracted from agarwood with water, was identified and was shown to generate LACs on heating, especially benzyl acetone. Agarotetrol and other chromone derivatives do not have a scent, although they are converted to LACs or other volatile compounds by heating to obtain the agarwood fragrance."
So heating will "evoke" the agarwood scent. Agarotetrol in agarwood through heat will emit low molecular weight aromatic compounds (LACs) such as Benzyl Acetone which has an odour profile of floral, herbal balsamic; these notes are easily detected from heating agarwood chips.
These oud wood chips when pulverised and soaked in water for several days before distillation to increase the LACS.
This process is one of the tricky parts because
Imagine, in a large batch when the distiller need to soak tons of wood for a more significant project, for example, 10kg of oud oil, for a particular perfume, how one would handle that to ensure the consistency in quality and quantity?