Ok, I think this is very interesting and it raises another question for me.
I am going to explain this a bit and then ask the question:
What I have achieved with fermentation is that carbohydrates in particular are needed so that the bacteria can actively continue the fermentation process.
What has also reached me is that microorganisms can produce fats, but as far as I know no original fermentation takes place with only an oil, simply because there are no carbohydrates present in the oils.
If high-grade oudh wood is used during distillation, there is relatively less active fermentation, simply because there is less carbohydrate available for the living ferments (because there are more oils than fresh wood).
If, on the other hand, there is relatively more white wood present (fresh/healthy wood), then the ferments have a lot of carbohydrates available.
I suspect that is what causes the cheesy smell (if there are no other factors).
My question from this is:
Can we assume that a cheesy oudh is an indicator of a low grade oudh that has been used, simply because white wood (much carbohydrates) is needed to get this scent?
I don’t think so.
Wood yields will have more to do with the OIL content of the wood.
Woods have both OIL and RESIN.
Usually a higher oil content wood will be more aromatic at room temp. The best woods usually have both oil AND resin.
At some point you’ll hit a point of Diminishing Returns - so the key will be in using grades high enough that you’re not simply wasting the wood.
This is why shavings will give such good oil. High oil content right up against that resin formation.
Low oil woods will yield 0.5-1mL / kg of wood
High oil woods can be as high as 12mL / kg. Sometimes even higher.
So we are talking a difference of 10g or so out of a kg in terms of oil in the wood, itself, which is expressed during distillation. Fermentation is there to break up the wood fibers which helps to release the oils in the wood. If it can’t escape the fiber - you can’t capture it in the receiver. That’s how fermentation “helps” the yields.
The alchemy of the scent is in maillard reactions during fermentation, same as in cooking. Both creating and releasing flavor that would not otherwise be present.
I always find it funny that people will eat bread (not the true flavor of wheat), enjoy vanilla or coffee (both fermented and not their “true” flavors) - but will then say oud oils with some fermentation aren’t “true” agarwood flavors. 🧐 By this definition - heating or burning it is also not a “true” flavor. Only the raw wood would be the true flavor.
Your premise about fermentation / low grade I would think would lead to lower grades of wood yielding higher yields of oil as a result, since there was more carbohydrate for fermentation.
Rather - I think both oil yield and skill and equipment (which can impact yields) would be a better indicator of the grades of wood used.
Oh - don’t forget distillation parameters (like temp and pressure), the set up, and type of distillation and equipment materials used.
At the end of the day - liking the scent of the oil is what matters, and that has both subjective and objective parameters.
Don’t forget the affect of aging and storage. Also factors in how something smells.
Maybe we all should drink a beer and relax (also not the true flavors of wheat and hops 🤫)
😉💪🏼🎉