Soaking and Oudh
Soaking the oudh in water has the most direct relationship with the scent profile and this can be explained in a scientific manner. Evidently increasing the water content of wood by soaking wood samples in water lowers the stiffness and strength of the wood. When wood is soaking in water and the water content of the wood is increased upto 200%, the cell walls fill with water. This filling of the cells causes the cell walls to expand, both a dimensional and structural change takes place. Water’s presence dramatically softens the cell walls.
The hydrogen bonds between different polymer chains in the crystalline cellulose microfibers start breaking. Hydrogen bonds form with water instead, as it is a small, polar molecule and so can get in between the polymer chains. Stronger hydrogen bonds are formed between cellulose and water than between cellulose and cellulose, making hydrogen bonding with water more favorable.
This softens the cellulose microfibers as they are no longer so strongly bonded to each other, making it easier to untangle and hence stretch the fibers. Leading to a decrease in the cellulose structure of the wood fibers allowing more of the oils trapped in the wood to be extracted in the distillation process.
Benefits to the Oudh Oil
With Oudh the soaking also has a further benefit and that is breaking down the resin that has hardened over time, this further allows for the release of rich oils that would otherwise be trapped in inside the resin structure. Note this is not claiming to turn resin into oil, but rather breaking down the resin to release the trapped oils inside it.
Distillation of oudh without soaking will generally produce a much lighter oil, missing the oudhyness, compared to if that same wood was soaked. Another important point to make here is Soaking and fermentation should not be confused, many mass production facilities ferment the young oudh trees in order to force a deeper scent. Fermentation is a form of scent manipulation. Soaking does not ferment the oudh and it does not alter the scent, soaking aids in releasing the actual scent of the wood, which would not otherwise be possible as much of the deeper oils would remain trapped. Science and historical experience prove the benefits of soaking in Oudh, the question is more around how to soak, for how long etc and not whether to soak.