“It drives me nuts when people refer to Proust and the madeleine.” Professor Kara Hoover is annoyed that I brought it up.

“It’s not about smell. I mean ultimately, you could say it is, but we have so many better smelly writers. Faulkner, Willa Cather; American writers are particularly smelly.”

Professor Hoover is an olfactory anthropologist, so she’s well versed in the literature of smell, and she’s right: Proust’s famous episode with the tea-soaked madeleine doesn’t actually mention aroma. But she concedes that it “captures the evoked memory well, and that’s why people like it.”

Proust’s passage is easy to relate to because we’ve all had that experience: catching a whiff of something that suddenly floods our brain with torrents of nostalgia—a momentarily-disorienting sense of emotional time travel.

Smell is unique among the senses in that it has an immediate, deep, and unconscious impact on memory—because there’s a direct neural pathway from the olfactory bulb to the amygdala, the part of the brain involved in the processing of memory, decision making, and emotional responses. Other senses don’t do this; they are processed consciously first, in other lobes of the brain, before being committed to memory. As Professor Hoover explains:

“The chemical senses [taste and smell] are the oldest senses; they were the first to evolve in all life on the planet.”

***

Professor Hoover tells me that our sense of smell is “ancient—part of the ‘first brain.’”

Smells are so powerful because deep within our most fundamental programming, we understand that ‘good’ smells could lead us to nourishment. It’s not too much of a stretch to say that smells are actually life-giving. When cartoon characters are lifted through the air on a wispy ribbon of aroma, drawing them involuntarily towards a pie cooling on a windowsill, the imagery rings true because sometimes, that’s how scent really makes us feel.

Although Proust’s madeleine and cartoon pies provide us with striking visuals to illustrate the power of smell, they are only able to have such an impact because the food in question is something out of the ordinary. If Proust ate madeleines every day, he wouldn’t have had such a profound experience. Likewise, if Yogi Bear was surrounded by pies, where would he float to? Would he even float at all? The immediate psychological impact of an aroma is diminished when it’s a mundane part of our everyday smellscape (a delightful new word I learned from Professor Hoover).

However, while the smells that are most familiar to us may not elicit these heightened, passionate reactions, their overall emotional substance is probably greater. These smells affect us in subtle but profound ways, like a gravitational pull. In Japan, among the most significant of these everyday smells is the humble, ubiquitous miso soup—and more directly, miso itself.

Miso is made by fermenting soybeans, rice, (and sometimes other grains and pulses) with kōji, a mould sometimes referred to as the national fungus of Japan. Kōji’s importance to Japanese gastronomy is hard to overstate, considering its essential role in the production of Japanese seasonings and drinks such as sake, soy sauce, miso, mirin, rice vinegar, and shochu.

Because of how they break down proteins into amino acids, kōji products are suffused with deep, satisfying umami, but they also leave behind an aromatic footprint not found in similar fermented products from other countries in East Asia.

The use of kōji, and the alchemical transformation it triggers in foods that contain it, is key to understanding Japanese cuisine. To me, one of the purest expressions of kōji is miso; its fruity-funky flavour calls to mind a vast range of other smells, from overripe pineapple to Parmesan cheese and Kalamata olives.

That really is down to the kōji itself—the substrate of miso is made of bland, not very fragrant ingredients, but kōji transforms them into something pungent and complex. To understand this process better, I spoke to two miso makers in London, Yuki Gomi and Kenji Morimoto.

***

From her airy home kitchen in Crystal Palace, Yuki Gomi teaches a wide range of Japanese cookery classes, from basic home cooking to more advanced courses in sushi and ramen. She is also one of the very few people in the UK who leads miso-making classes for the kōji-curious. While it is uncommon for people to make their own miso in Japan, she has been doing it with her family since childhood.

“Not many people make miso nowadays, but traditionally to Japanese people it was very important,” she says, explaining how the word for homemade miso, temae miso, is used as an expression to humble oneself while talking about something you’re proud of. (You’d use it along similar lines to “I don’t mean to brag but…”)

This indicates how making miso yourself is a bit of a flex—it takes time and effort, and it isn’t really necessary—but the end product is something special.

“I always do a blind miso tasting with the students, and I am always proud of myself because everybody loves my miso the most,” Yuki says. Temae miso.

““The chemical senses are the oldest senses; they were the first to evolve in all life on the planet.””

— Professor Kara Hoover

Yuki compares making miso to making wine or sourdough bread, in the sense that even if you follow the same method each time, the results can be very different depending on minor variations in the raw ingredients and the fermentation process.

“My recipe is exactly the same as my mother’s, but it comes out so different,” she says.

Yuki is a global miso evangelist—using one traditional recipe, a multitude of unique, individual, local misos can be made, all through the magic of kōji. Her passion is to get everybody making “London miso,” or, in the case of her online students in the US, ‘”Las Vegas miso,” “Wisconsin miso,” or “Chicago miso.”

”That’s my real mission,” she says. “It’s fascinating to me.”

***

The radical transformation and unpredictable nature of miso fermentation is “pure alchemy,” says Kenji Morimoto, who has been experimenting with kōji as a hobby for many years, and recently began hosting miso-making workshops in his home. For Kenji, a fourth-generation Japanese-American now living in Brixton, it has been a pastime that spiritually connects him to his heritage in more ways than one.

“I came from such a close-knit Japanese-American community, where we'd see each other all the time, every Sunday at temple, and all my friends were nearby,” he explains.

“After moving to the UK, I really missed the connection to that culture. Obviously, I have friends here, but it's so different when you have people who look like you and have the same history as you. So diving headfirst into something very, very Japanese was deliberate. I wanted to stay connected.”

“I was raised Buddhist,” Kenji continues. “For me, the catharsis and process of miso making is really powerful, and I know it sounds cliché, but I find it very Buddhist. There’s so much outside of your control, and seeing how the change in temperature accelerates the fermentation and how the tamari [a Japanese equivalent to soy sauce] starts to pool—it's doing its own thing.”

Kenji says that waiting for miso to fully ferment, which takes six months to a year, is itself a lesson in appreciating the passage of time.

At Kenji’s house, I get my hands dirty—or mouldy, to be more accurate—by making my own miso. When I arrive, Kenji has actually done the hard part for me: he’s already got some rice inoculated with kōji, ready to go, as well as a bowl of boiled and cooled soybeans.

I came to discuss the olfactory qualities of kōji, but I’m struck by its tactility as well. The kōji rice has a tacky, pasty, and slightly furry quality that seems like it would make a good adhesive; it feels eager to cling to stuff, which, I suppose, is exactly what it’s meant to do.

As for its smell, it has the same fruity-fungal character I would expect from good sake or miso, but more subtle. There are floral notes of white peach, lychee, and melon along with earthy, nutty, mushroomy aromas. The overall effect is similar to a washed-rind cheese, and indeed, kōji is now being used by home fermenting enthusiasts as well as food start-ups to produce plant-based cheese substitutes.

My hypothesis when I first started researching kōji was that it would be immutable and overriding in anything it’s applied to, that ferments made with kōji would have a distinct ‘Japaneseness’ to them regardless of what raw ingredients were used. Turns out I was completely wrong.

Kenji has applied kōji to black kidney beans, sardine and mackerel guts, butternut squash, shiitake mushrooms, prawn heads, pico de gallo, lemon with pul biber, chimichurri, and even chocolate cake. All of them are delicious, but none of them taste much like miso, nor do they showcase the unique aromas of kōji.

Both Kenji and Yuki agree that ferments based on anything other than the typical soybeans and grains used in Japan aren’t really miso, because they simply don’t taste the same, and might not be used in the same way. There is even an obscure type of miso in Japan called Kinzanji miso made from vegetables, eaten like a pickle rather than a seasoning. The relatively neutral taste of soybeans and rice is what allows miso to develop those unique kōji aromas so well, which is ultimately what imparts a ‘Japanese’ flavour to food.

***

“I used to live in Chicago,” Yuki tells me. “When you first go to America… you can smell America. And when I go back to Japan, I can smell Japan. And the smell of Japan is… I wouldn’t say kōji, but almost, because there’s so much of it around!”

Sure enough, the aroma of kōji products—miso among them—is as unavoidable almost as soon as you step off the plane at Narita Airport.

““Miso always reminds me of home, and breakfast—the beginning of the day.””

— Yuki Gomi

“Miso always reminds me of home, and breakfast—the beginning of the day,” Yuki continues. “My mom always made Japanese breakfast for me, so waking up in the morning smells of dashi and miso. Funny enough, every time I feel ill, or when I was pregnant and had morning sickness, I always craved miso. Maybe that’s because it’s like, mother’s food, isn’t it?”

For Kenji, miso soup reminds him of home in a different way.

“Growing up in a Buddhist temple, we would always have massive vats of miso soup cooking in the kitchen for large events. That's my memory of miso-shiru [miso soup]—walking into the temple kitchen and being hit with that smell,” he says.

“My grandmother used to make it, but it wasn't something we would make at home.”

Professor Hoover told me that her primary interest is in sensory ecology—the landscape that shapes you and your culture, and also how you transfer the knowledge of what's familiar when you move into new territories or your environment changes. This is why recreating the flavours and aromas of home is so universally important to the expat or immigrant experience—sensory cues are a powerful way to feel at home, away from home.

Kenji told me he was also drawn to miso-making because he naturally enjoys nurturing things, and that in a very literal sense, nurturing kōji-based ferments also nurtures Japanese culture. It is a way of planting a little bit of Japan and helping it grow, anywhere in the world.

***

To book Yuki Gomi’s classes, please visit her website. She also offers consultancy services and events catering.

For information on Kenji Morimoto’s kōji workshops, follow him on Instagram.