We’ve done taste buds, tongues and chewing, so at last we can get around to perhaps the most important part of tasting: smelling. For it’s in the nasal cavities where the majority of the sense we think of as “tasting” occurs.
As anyone who’s ever had a cold can tell you, things don’t have much flavor when you can’t smell. The reason is because plugged sinuses prevent the essential oils liberated by chewing from reaching our olfactory receptors.
What are olfactory receptors? Proteins, basically, very similar to the ones in the taste buds on the tongue. But whereas each human tongue has something on the order of 10,000 taste buds with a few hundred receptors each, the roof of the human nasal cavity contains something on the order of 50 million olfactory receptors which bond (again, only very briefly) with odor molecules as they pass by.
Why so many receptors? Well, when you consider that a typical herb or vegetable may contain several dozen different types of essential oils — fruits can contain up to several hundred — there’s an awful lot of data wafting through our nasal cavities. We need a lot of gear to process it.
Which brings up an interesting point about tasting: that’s it’s intimately related to breathing and air flow, both through the nose and through the mouth. That is why professional tasters (yes there is such a thing) do so much breathing as they ply their trade.
To get a sense for the special style of breathing professional tasters typically employ, imagine the act of smacking your lips. Pretend you’re trying to entice a baby into eating a spoonful of strained carrots: Oooh look, yummy carrots…smack smack smack. Got that? Now do it fast: smack-smack-smack-smack-smack. Keep it up while you inhale deeply through both your nose and mouth.
Feel like a total flipping idiot? Then you’re doing it right, and may have a big career ahead of you as a pro taster. It’s exactly what these people do when they’re sampling, say, a cup of coffee. Slurp…smack- smack-smack-smack…slurp…smack-smack-smack-smack.
From the outside it appears utterly ridiculous, but there’s clear method there. Accurate tasting means utilizing as much of the sensory hardware in our heads as possible. To activate it you need plenty of air. It keeps the essential oils circulating, the receptor proteins bonding and releasing, and the brain lighting up like a Christmas tree.