Exploring the 5 Senses: A Taste Experiment With Apple & Onion

Sliced red onions

As I’ve mentioned before, I’m working on a book about the body and the five senses. What a delightful project! My prediction is that by getting back inside my body by systematically exploring my senses, I can shake my mind awake.
As usual, as part of my research I’m using myself as guinea pig—and I’m also involving the innocent bystanders around me. Last year I recruited my daughters Eliza and Eleanor for
an experiment involving Life Savers as a tool to explore the relationships among smell, taste, and flavor. More recently, when Eliza was home, the three of us tried a popular taste exercise using apples and onions.

Taste is an unusual sense, because while we experience flavor in our mouths, those flavors are mostly a product of smells. The fives tastes—sweet, sour, bitter, salty, umami—are quite different from flavor, which is a combination of taste and smell.

As we eat, we smell our food twice. First, there’s orthonasal olfaction, the familiar kind of smelling that we do through our nose, when we inhale the smells rising from a plate of lasagna. But another kind of smelling is crucial to our sense of flavor: in retronasal olfaction, we also smell food when it’s in our mouth, because as we exhale, scents from the food are sent through an opening at the back of the mouth, up to the nose.

In what’s called the “olfactory location illusion,” we think that the food’s flavor is coming from our mouth, even though much of that flavor is furnished by the nose. Sometimes people think that their sense of taste is impaired when it’s actually their sense of smell.

This relationship has been highlighted in the time of the pandemic. In some people, decrease or loss of the ability to smell is a symptom of Covid-19. Many people think they’ve lost their sense of taste, because that’s what they notice, but in fact it’s their sense of smell that’s impaired. Now that I’ve studied the sense of smell, I realize what a terrible loss this is; although we often take the sense of smell for granted, it’s an essential element to our sense of vitality, connection, and awareness.

I have several friends who lost their sense of smell from Covid-19; fortunately, they’ve all got it back, more or less.

For this apple and onion experiment, Eleanor cut up cubes of apple and onion, and we took turns pinching our noses to taste and guess; according to what I’d read, if we couldn’t smell, we wouldn’t be able to tell the apple from the onion.

But even without smell, we all easily guessed correctly. True, for the first few seconds, it was difficult to discern the difference, and I was surprised at the initial sweetness of the onion. But an onion’s unmistakable bite quickly gave it away.

“Let’s try again with a potato,” I suggested, and Eleanor obligingly cut cubes again. Again, we could easily tell the difference. So much for that experiment.

Have you ever tried an experiment like this—or realized that your sense of taste has been affected by a change in your sense of smell?



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