Tasting synthetics or cutting agents is like licking cactus leaf. You'd be gargling trying to get rid of the bitterness and the irritation in your throat for the rest of the day. So when push comes to shove, tasting for synthetics is a quick way to tell the purity of an oil. Needless to say, I don't do that myself, nor do I recommend anyone doing it. But it works in theory.
Obviously, that's not what
@Taha is doing in the video. I can't speak on his behalf, but the taste of oud oil actually goes some way in telling you the quality of the wood, and also the cleanliness of the distillation. If you've ever sampled different kinds of olive oil, it's immediately obvious which ones are the riper, better cultivated ones. The almost peppery bitterness, the twang it leaves on your tongue afterward, etc. Similar thing here.
We've had some people over for a tasting session. After the initial reluctance to add a drop to their tea, or if you're more daring, take a drop straight on the tongue, the experience usually ends up in a "Wow... I see!" moment. Especially when you taste the higher end oils. Purple Kinam is the go-to reference for us. Taste it and your whole head gets permeated by the very scent you smell. There's an almost menthol like coolness that sizzles through your sinuses into your forehead, and a little bit of a buzz that hits you soon after. A calming, spaced out feeling, not dissimilar to the effects of chewing on a betel nut.
But taste a regular, lower grade oil, and you wouldn't know what you're tasting if you didn't know it was oud. It just tastes 'oily'. It's quite illuminating to do these back and forth tastings between different caliber oils because you quickly see a pattern emerge, where the ones that are supposed to be higher quality do in fact tickle your taste buds a lot more.
Remember that in Chinese tradition oud oil is first and foremost a medicine. And like crushed leaves and herbal pastes, you can tell by the sharpness of the taste which ones are more resinous, more intense, and likely pack more medicinal oomph with greater concentrations of antioxidants, etc.
But more than any of this, what Taha was probably doing is approaching the oil holistically. The taste tells you something about the oil, the kind of wood, the distillation, and ultimately the quality that adds to what you pick up in the smell. Flip the story around and it's like when the Japanese Emperor would take a whiff of his tea before taking a sip. If the smell wasn't right, he wouldn't even bother drinking the tea. The scent imparts certain information that the taste doesn't, and vice versa. And it all adds to the completeness of the experience. (PS: If you haven't read it yet,
here's more on why coffee never tastes as good as it smells.)
We all know of a certain someone who goes as far as injecting his steak with oud smoke.... he gets what I'm talking about! (That was actually a great illustration of this idea, since
@Joyoud noticed what a difference the sinking-grade chips made compared to the lower grade stuff.)
Disclaimer: Before anyone gets on my case, I do NOT encourage ingesting oud oil. Do so at your own discretion, and in consultation with an experienced Chinese Medicine practitioner. You can't just drink any oud, especially since (as Taha knows all too well) many ouds contain all sorts of things that are not meant to enter the human body. I think Ensar mentioned this already, but even if pure oud, Chinese connoisseurs wouldn't even think of tasting oil if it was soaked (due to the fungi and bacteria that grows in the process.) We happily try our own because we know how it was made.