I was preparing dinner the other night and washing dishes at the sink when a foul odor seemed to come out of nowhere. “What is THAT?” I shrieked. “What is what?” responded my husband, who was in the kitchen but behind me. “That horrible smell. Where is it coming from?” I turned toward my husband, who was laughing. “I just took some cheese out,” he said. I spotted the cheese, a favorite of mine, and almost instantly the offensive aroma became appealing. How did that happen? I figured Harold McGee, author of Nose Dive: A Field Guide to the World’s Smells, would know.

I spoke to McGee by phone the next day and have edited our conversation for clarity and brevity.

It’s surprising that we like cheese at all, given how close some of its aromas come to aromas that people deem unpleasant or even disgusting.

McGee: You’re right to find that curious. Washed-rind cheeses, which are often the most stinky, are the most reminiscent of our own bodies. In the book’s chapter on human body odors, I speculate that the reason people went to the trouble of washing cheese with brine was to develop those flavors. I wondered whether it was of interest to our ancestors to make something from animals that reminded them of themselves. Maybe it made those materials more familiar and therefore more desirable?

There’s the theory of “constrained risk” to explain why we like chili peppers and go on roller coaster rides. It’s inflicting a kind of unpleasantness on ourselves, but it ends up being pleasant because we know it’s safe. Maybe it’s the same kind of thing with stinky cheeses.

A lot of us have had that experience of smelling something familiar, but we can’t put the name to it. Why does that happen? We easily identify what we see. Why aren’t we better at identifying smells?

Neurobiologists have debates over this. One theory is that it just takes a lot of brain processing power. (Recalling) where we’ve encountered a smell takes a lot of work unless we’re trained at it, and we can be. With vision, the input is constant, so changes are immediately apparent. Smell is more episodic. It may have been three years since you last encountered that smell, so you have to dive deeper.

How did your own sense of smell change over the course of researching your book? Did you become more perceptive?

I lost my sense of smell while writing this book, probably from a (pre-Covid) viral infection. I woke up one morning feeling normal and made coffee and realized I wasn’t getting aroma from it. It was hot, astringent, bitter, nasty. I contacted my friends in the olfaction world and asked, “Should I be concerned? Is there anything I can do?” and they said, “We have no idea.” One positive thing about Covid is that it has brought more scientific and medical attention to smell, a sense that’s been largely neglected. There’s no treatment (for loss of smell), but after two months it began to come back.

If you wanted to sharpen your sense of smell, how would you go about it?

It really is a matter of repetition, concentration and organization. You can go to your spice cabinet and take out five spices every day and register what they smell like. Then you take out something like curry powder, a blend, and try to pick out the spices that go into that blend. These days, there’s a huge availability of single molecules for use by perfumers, so you can expand your experience beyond what you have in your kitchen. There’s that kit, Le Nez, for wine training. It’s a prepackaged box of 30 or 40 molecules important in wine. It’s expensive, but I know a lot of wine lovers who have bought it.

We’ve all heard about super tasters who have a low tolerance for bitter. But in your research, did you encounter people who were super smellers, with extremely acute senses of smell?

I’ve met people like that over the years, and I would say a lot of people in the food and drinks world are like that. Mandy Aftel is very much like that.

We all have different apparatuses for detecting and making sense of smells. These are our olfactory receptors, and nobody has every possible one, so we all have blankness to one thing or another. The way we process smells has to do with our brains and our experience. People can be trained to be as sensitive to and as adept at identifying smells as a perfumer.

Why do our dogs have better senses of smell than we do?

For generations we had this idea that animals are better at smell than we are. Because we considered smell to be an “animal” sense, we use sight and hearing to do “higher things” in life. We considered taste and smell to have more to do with just feeding our organisms and not capable of the same sort of refinement. It turns out that’s not true. People recently have studied animals’ sensitivity to particular molecules—their thresholds—and all mammals are kind of the same. Our impression that animals are better at it has to do with the fact that they’re doing it all the time. A dog whose eyes are less than a foot off the ground is going to be paying attention to what’s on the ground, while we’ve got other things to occupy us. We’re more capable than we give ourselves credit for.

What cheeses do you find most pleasing aromatically?

That’s a tough one because I love the variety. In the late 1990s, I lived for a year in the French countryside, and I experienced two things there that I still love. One is Vacherin Mont d’Or, which is why I like Harbison, often the closest you can come to the Vacherin experience here. [A ripe Jasper Hill Harbison was the pungent cheese my husband took out of the fridge.] And the other is a Tomme de Savoie that has been overrun with cheese mites. I remember walking to markets in France and being able to smell it a block away. It’s hard to describe but unmistakable. I asked the guy who discovered the molecule that cheese mites emit, and neither one of us could do any better than “kind of lemony.” I enjoy it not because it’s intrinsically pleasing, but because it’s interesting. And I really love Andante Figaro. That combination of goat’s milk and fig leaf is magical.