Camille doesn't drink wine. She tastes it anyway

In the series Drops of God, Camille Léger can't stand a drop of wine. When she was a child, her father would take her down to the cellar, blindfold her and slip pieces of fruit into her mouth, which she had to name on the spot. Something broke that day, and ever since, wine has filled her with a physical aversion. Yet when her father dies, she learns that to inherit his cellar, she'll have to identify great wines blind.

The Apple TV+ series, adapted from a Japanese manga, invented this trauma: in the manga, the heir is a man who drinks without the slightest trouble. But the writers built their plot on a truth most wine lovers never put to use. Most of what Camille is looking for in her glass has very little to do with her mouth.

Five tastes, and that's it

Your tongue can recognize sweet, salty, sour, bitter and umami. That's the whole catalog. Carole Prost, who studies odor molecules in Nantes, has a way of putting it that's hard to argue with: if you were only a tongue, you couldn't recognize a tomato. You wouldn't recognize a Pinot Noir either.

Even tannin escapes the tongue. Its molecules latch onto the proteins in your saliva, which stops lubricating, and your mouth turns rough: tannin is something you feel more than something you taste.

Everything else comes in through the nose: cherry, chalk, leather, forest floor, and just about everything that makes a wine unmistakably itself. Researchers at INRAE, France's national research institute for agriculture, food and the environment, estimate that smell accounts for about three quarters of what you perceive when you taste something. What you call a wine's "taste" is mostly its smell.

Two doors for the same smell

There are two routes to your nose, and knowing which one you're using changes the way you taste.

The first goes through your nostrils: you stick your nose in the glass and breathe in. That's what we call its smell. The second starts in your mouth, where the wine warms up, mixes with your saliva and releases its molecules, which rise through the back of your throat. This time, we call it flavor. Same wine, same nose, but a different door, and a different perception.

This second route has a quirk, demonstrated in 2015 by a Yale team that included Gordon Shepherd, the neurobiologist who coined the word "neurogastronomy": it only works when you breathe out. By rebuilding a human throat from medical scans, the researchers saw that when you breathe in, the air forms a sort of curtain that keeps the molecules in your mouth from drifting toward your lungs. When you breathe out, the airflow sweeps the area and pushes them up to your nose.

That explains a scene you've surely witnessed: someone holds a sip in their mouth, closes their eyes and breathes out slowly through the nose, looking as if they're pondering the meaning of life. They're simply opening the only door that works.

The day everything went dark

During the COVID pandemic, some wine professionals lived through the opposite of Camille's problem: they could drink as much as they liked, but the wine had nothing left to say to them.

Philippe Faure-Brac, named the world's best sommelier in 1992, has described that spring of 2020 when smells had simply vanished. Serge Dubois, vice president of the International Union of Oenologists, could no longer tell pastis, the anise-flavored French aperitif, from a glass of wine. Federica Zanghirella, vice president of Britain's sommelier association, spent an online tasting class apologizing to her students for the mediocre supermarket wines she was having them taste. The wines were fine. It was her.

They all said they had lost their sense of taste. Yet their tongues worked perfectly: they still picked up sweet, sour and bitter. It was their noses that had gone dark, and with them, almost all of the wine.

The eye gets the last word

One last story, slightly humbling for the professionals. In 2001, two Bordeaux researchers, Gil Morrot and Frédéric Brochet, asked fifty-four enology students to describe a white wine, then the same white wine dyed red with an odorless grape pigment. The students described the second one with the words they reserved for red wine, and dropped the ones they had found for the white a week earlier.

The nose works better when the eye keeps quiet. So closing your eyes to smell a wine isn't just for show.