The Nose Knows

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.

6 thoughts on “The Nose Knows”

  1. Does a person who eats normally just get a diluted taste of what a professional detects, or does overlooking those nuances lead to a different taste altogether?

    1. Hey Catherine! My experience with professional tasters is limited, but I’d say that the main reason they’re there is to prize out the minute differences that most of the rest of us might not be consciously be aware of, but which might tip the balance between a merely good product and an excellent one. Being accustomed to taking about flavors for a living, they’re also good at putting into words things that regular people can merely feel.

      Thanks for the question!

      – Joe

  2. Hi Joe,

    If bonding with receptors on your tongue or in your nose only happens briefly, then why do some tastes remain for a long time? Tastes like garlic or onion can stay with you for a very long time even hours whereas chocolate is gone in seconds or minutes. Personally, I would prefer that the chocolate hung around for hours… maybe I’d eat less of it then.


    1. Hey Eva!

      That we taste garlic so long after we’ve eaten it has less to do with the length of time it bonds to our taste buds than with the sheer pungency of the sulfurous compounds it contains, and the fact that even tiny traces left hiding among our teeth and gums are enough to give us the lingering sensation for ours. Of course some traces also come back up in burps, which tends to ruin the positive effect of many minutes of thorough brushing. But I’m with you…why can’t more pleasant foods do that? Thanks for the question!

      – Joe

  3. Eyes help too. A surprising amount. There’s a little demonstration used at science fairs where kids (and parents) are given flavoured drinks coloured “wrongly” – orange coloured raspberry, green coloured orange etc – to identify. Quite amazing the number of people who identify according to what they see rather than what they taste.

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