Fermentation Nation, Tabesugi Podcast Episode 3

By The byFood Team
Updated: August 16, 2022

What do soy sauce, miso, and sake have in common? They're all fermented foods! In "Fermentation Nation," episode 3 of Tabesugi podcast, we delve into the world of Japanese fermented foods. Tabesugi's host Emilie Lauer is joined by Quentin from France and Valeria from Italy, to see if they can tempt strangers in Shibuya with natto. Known for its neba-neba “sticky” texture and signature aroma, natto is a fermented soybean product that’s famous (or rather, infamous) among foreigners in Japan. 

Then we’ll meet Shirley, a fermented food fanatic who says soy sauce runs in her veins. As she bustles around the kitchen, whipping up ichijiu-sansai, Shirley discusses her love for koji, miso, and soy sauce; speaks about the health benefits of fermented foods; and reveals a little-known tip for eating natto.

Editor's Note (8/13/2020): This podcast episode references Shirley's cooking classes; these classes are now unavailable as she is planning to move from Tokyo.

Curious to learn more about Japanese home cooking? Browse cooking classes in Japan! Every booking on byFood helps children in need through the Food for Happiness Program. 

Missed our previous episodes? Tune into Tabesugi episode 1, Welcome to Japan, or episode 2, Noodle Fever.

A Japanese woman stands in her kitchen behind a table laden with all manner of sake bottles, natto, miso, and other fermented foodsA spread of Japanese fermented food ingredients on the table, like sake, natto, miso, and kojiShirley, a Japanese woman stands behind her kitchen table, smiling. There are a variety of fermented foods on the table like miso paste, soybeans, koji, sake, and nattoTwo bright orange salmon fillets are grilling over a portable burnerThe Japanese mortar and pestle (suribachi and surikogi) are being used to mash a mix of tofu and sesame seedsA mix of shiroae (a dish made of tofu and sesame seeds) with orange and green flecks of vegetablesAn overhead image of a wooden tray with several small dishes, a striped blue bowl, octagonal small sauce dish, chopsticks, and a rectangular white plateOverhead shot of a container of nukazuke, a fermented mixture of rice bran that is used to make Japanese picklesOverhead shot of a round white table with two place settings. The plates have grilled salmon, bowls of white rice, miso soup, pickled dishes, and teaAn image of "Ichijiu Sansai," the traditional Japanese meal layout with one soup and three dishes. There is a bowl of white rice, miso soup, shiroae, Japanese pickles, and grilled salmonA dark-haired owman bugging her small chihuahua, Colin, in her Japanese kitchen

Tabesugi Episode 3 “Fermentation Nation” - Full Transcript

EMILIE: When it comes down to food, Japan has many specialties that just make you mouth water instantly, I mean who doesn’t crave sushi, ramen, gyoza, tempura, Kobe beef, yakisoba or even takoyaki.

And then there is that one sticky food that scares most foreigners, me included…yes I’m talking about natto! And if you haven’t yet heard of it, well that’s what we’re here for!

[TABESUGI INTRO: slurping, sound of gas stove igniting, glasses clinking, crunching interspersed with different voices saying “tabesugi.”]

EMILIE: You’re listening to Tabesugi podcast. Tabesugi means “overeating” in Japanese and this is definitely one of our favorite pastimes! We are here to bring you insights into Japanese culture, history and people through the lens of food. I’m your host Emilie Lauer, let’s go on this journey together! This is episode 2, Noodle Fever.

BREAK: Tabesugi is brought to you by, the one-stop platform for foodie travelers in Japan, where you can explore food tours, cooking classes, tastings, and dining experiences, along with food guides and videos. Every booking on helps children in need around the world through the Food for Happiness Program. Just by enjoying a meal in Japan, you can help children in developing countries get access to necessities like nutritious meals, schools, and housing, so they can grow up happy and healthy.

EMILIE: I discovered Natto when I landed in Japan and what I had heard of it didn’t exactly make me excited to try it. Indeed, natto is a fermented soy bean product often described as a “neba-neba” or sticky food. Foreigner visitors to Japan say it tastes bad, smells terrible and has a weird texture. But it has a special place in the hearts of the Japanese. People here have grown up eating this affordable and nutritious dish. But, Since I have a texture problem, trust me when I say that I answered “when pigs fly” when asked if I will try natto. But then when this episode’s concept was decided on, well I knew I had to do it for the podcast. But no way will I try it on my own, so I gathered Quentin and Valeria, two interns at byFood who, don’t ask me why, both love natto. All together we headed to Shibuya, the one place in Tokyo where you are 100% sure to find tourists 24/7.

EMILIE: Do you guys like natto?

VALLE: Kind of. Some times. With the mustard yes, and the sauce yes, natto by itself, not that much.

EMILIE: When do you eat it?

VALLE: I actually eat it as a snack when I want to. Sometimes I want natto.

EMILIE: Ok, so sometimes you want natto.

VALLE: It’s something I didn’t love recently but with the sauce, it’s just a different thing.

EMILIE: How about you?

QUENTIN: I eat that every morning. That’s really my thing every morning. First thing, I eat natto.

EMILIE: For real?

QUENTIN: For real. Every morning. No exception. 7 days a week. 

EMILIE: How do you prepare it?

QUENTIN: You just open the box and inside, there is the natto but without the sauce, so you add soy sauce, and if you want, you add the mustard then, and then you mix it and it brings something like really really bubbly and it’s a bit smelly but I’m used to it so it’s ok.

EMILIE: Do you eat it like that or do you eat it with rice?

QUENTIN: I only eat natto.

EMILIE: Only natto. Ok, so let’s see what people think about it. 

Earlier that morning, I had bought a box of fresh natto. Traditionally wrapped in dry straw, but now commercialized in plastic box or cup, natto is found pretty easily in Japan at every convenience store and supermarket. The natto comes with packets of soy sauce and karashi (spicy mustard), so you can then decide which sauce you want to use if any. This time we only used soy sauce, as some people might not like mustard. So just like that, in the middle of Hachiko Square, I made people try natto for the first time.

EMILIE: Have you tried natto yet?

MAN : No, I only saw it a bit, in images. It’s strange, the look of it is very different.

EMILIE: Let’s go for it.

MAN: Okay, oh yes.

EMILIE: (laughs) What does it taste like?

[Montage of Answers]

ANSWER 1: It’s not fresh any more. A bit too old or something, the taste and the texture.

ANSWER 2: I’m not sure if I would have it again. (laughs) I mean it’s not disgusting but I wouldn’t try it again.

ANSWER 3: I heard a lot about natto. It smells like feet, it has the consistency of cheese and somehow it’s also a bean. You know, that was not actually bad actually. It taste like something I have had before, I don’t know what. But it does not taste like beans.

ANSWER 4: That’s not too bad. I love it. I want it at home. I would eat it every morning for breakfast. 

ANSWER 5: I mean, it’s just basically flavorless. I don’t even know how to combine it with food even.

ANSWER 6: It’s a bit strange. It’s sticky in the mouth and the taste is very strong.

ANSWER 7: A bit like coffee. 

ANSWER 8: It’s good, it’s sticky and a bit salty, but I’d eat it again. It’s not bad, I like it. Maybe with some rice and some vegetables. I like it. 

EMILIE: Actually, there are many ways to eat natto. The most common one is with rice that you can then top up with green onions, egg yolk, kimchi, cheese and so on. Natto can also be used on toast, gyoza and even sushi rolls. There are many types of natto, with different size beans, and the smaller the bean is, the stickier it is. Considered a superfood, natto is a good source of protein, fiber, and vitamins; and because it is a fermented food, it contains probiotics, some good bacteria that helps your internal flora.

Natto has a defined place in the Japanese diet, as it is a healthy dish, which has been eaten for centuries. And because the people who tried it find it Nattobad, I have no choice other than to give it a go!

EMILIE: I’m scared guys. I’m so scared.

VALLE: Are you ready?

EMILIE: No. I’m not. Everyone was eating it and I was like, yes, no, yes, no.

VALLE: Are you scared about the texture or the flavor?

EMILIE: Everything. I hate the texture. I hate the flavor. I don’t know… If it tastes like coffee, people say, that’s fine but... 

VALLE: Okay, are you ready?

EMILIE: It’s very sticky. Man, the smell is strong. Okay, one, two, three! 

VALLE: (laughs)

EMILIE: It’s gross! I can’t. The texture is weird, it’s sticky, it’s too strong, I don’ t understand how people say tasteless. It’s very strong in the taste. I don’t know.

EMILIE: You should have seen my face…Never again. I actually only did it for the episode, I never intended to try natto otherwise. But you know what, I’m proud I did try. While natto is notorious among foreigners, Japanese people love it. And it’s pretty much a staple of the traditional Japanese breakfast. It’s a big part of the healthy lifestyle culture here. Natto even has its own museum in Ibaraki prefecture, north-east of Tokyo. You can also find all-you-can-eat natto restaurants serving up natto all day, every day. But how should you really eat natto?

SHIRLEY: Natto bacteria is known as repairing our cell. Actually the wall part of the cell. And cells are repaired while we are sleeping, like 10pm to 2am. So it is good to take natto at dinner time.

EMILIE: Oh. Not in the morning.

SHIRLEY: Not in the morning. And also, the temperature is important. 45-48 degrees celcius is the best temperature for the natto bacteria. It becomes very active. So you’d better eat your natto not cold, like right out from your fridge. You’d better leave it at room temperature. Some people put their natto on their Japanese curry rice. But I think it’s a good idea because the natto will warm up. You can also make pasta, fried rice, as long as you don’t put the sauce and mustard in it, it doesn’t have a strong flavor. The issue is about the texture. So, you can be very creative with your cooking.

EMILIE: Natto is not only a fermented soy bean dish, it is also a useful ingredient with infinite potential. There are so many ways it can be cooked and eaten. But natto is not the only product Japan has to offer in terms of fermented food. The Japanese cuisine includes many dishes like natto. In fact, fermented food is one of the secrets to Japanese youth and health. But how do they eat it? How do they cook it? Japanese fermented food is a world of its own, and I had the good fortune to meet up with a Japanese home-cooking expert and fermentation queen!  

SHIRLEY: I was born to love it. It was there when I was born and I just like the taste. I love the smell, and for now I know how it is good for you, so I just love the existence of fermented food. My blood is soy sauce (laughs). 

EMILIE: That was Shirley. Shirley is an unconditional fermented food lover. Whether it be natto or miso, she knows everything about fermentation. Shirley is your typical home cook, she does everything by hand, gets her recipes from previous generations, and loves to feed people. She is so fond of fermented food that she cooks it and eats it every single day. Her pantry is actually full of fermented goodies.

SHIRLEY: We have a few kinds of miso and handmade mirin and koji seasonings. Those are, of course, handmade. And something very surprising (laughs). 

EMILIE: What is it?

SHIRLEY: This is miso. 1300 years ago, the miso came like this from China with Buddhism. And we also have natto. And I also have nuka pickles for you. Nukazuke. 

EMILIE: If you haven’t heard of nukazuke pickles, you’re not alone. It is not that well known amongst foreigners, but Nukazuke is a traditional side dish in Japan. It’s basically pickled vegetables such as cucumber, carrot, and aubergine or eggplant depending which country you’re listening from . They are first soaked in rice bran and then fermented with koji mold. It comes as a brown paste, that has a very strong smell and taste. It’s definitely a hit or miss.

Shirley is not only a home cook, she is also a passionate cooking instructor who shares her love for Japanese food with others, especially foreign visitors to Japan. She conveys her knowledge and enthusiasm for food during cooking classes, where guests can learn how to make delicious Japanese meals at Shirley’s cozy home in Tokyo. Shirley’s classes are special, they’re intimate. And as a fermented food expert, Shirley offers two classes where you get to experiment with fermentation in the kitchen, a Miso Making Class and a Cooking with Koji Class, both available on

So, one afternoon, Shirley invited me over to discover more about fermentation. To be honest with you, I had no clue about fermented food, I wasn’t even sure I would like it. I had already tried natto and that was definitely not a success. So I was a bit scared to try other fermented food, but the way Shirley cooks it, is different, it’s good, it’s authentic Japanese food just like mom makes it. She started by giving me a taste of her homemade koji.

SHIRLEY: Let’s start with salt koji. We’re gonna make this later. This is salt koji, this is soy sauce koji, and sweet koji. This sweet koji is made from white rice, and this brown one is made from brown rice, and this is also sweet. Ok, let’s try. You can start. We need a smaller-- There you are.

EMILIE: Arigato

SHIRLEY: This is salt, salt koji. 

EMILIE: So the koji’s already inside.

SHIRLEY: Yes, koji and salt and water

EMILIE: When do you eat that?

SHIRLEY: Oh, I use this instead of salt. 

EMILIE: Oh, it’s very salty.

SHIRLEY: Yes, it is.

EMILIE: I love salt.

SHIRLEY: (Laughs) I do too. And you can try this soy sauce. This is soy sauce plus koji.

EMILIE: It’s very good. It’s very strong in taste, but it’s not too strong. Well, I like it so. It’s not too strong but it’s stronger than normal soy sauce?

SHIRLEY: Yes, it’s much richer because of amino acids from the koji. And this is sweet koji.

EMILIE: Ooh, that’s not the same texture.

SHIRLEY: Koji and mochi rice and water.


SHIRLEY: Sweet isn’t it?

EMILIE: And it’s only rice and water, there’s no sugar. 

SHIRLEY: No sugar.

EMILIE: So it’s good for health and it’s sweet.


EMILIE: I like it.

SHIRLEY: I like it too. Okay and there are ways to ferment food. Simply add salt and sugar to the ingredients and let the good bacteria grow to be edible. Koji bacteria is used only in Japan. In Japan, sprinkling bacteria onto the ingredients are very typical. 

EMILIE: Koji is actually the key to Japanese fermentation. Koji is a filamentous mushroom or mold used to ferment rice or soybeans. It is a necessity in the fermentation process as it consumes the starch to produce sugar when it comes to make sake or any Japanese rice wine. In the case of miso or soy sauce, the koji mold consumes proteins to produce amino acids, and those amino acids give them that famous umami flavor.

But why fermented food is so good for you?

SHIRLEY: Oh, Japanese food is very healthy. And also, fermented food is really good for you. Indeed, drinking the sweet koji with soy milk, it cured my anemia. And after that I never get dizzy, I never get tired, I feel energetic. 

EMILIE: If a simple glass of sweet koji and soy milk cured Shirley’s anemia, the effect of fermented food on the body do not stop there. Fermented food has proven digestives health benefits due to the probiotics they contain. It improves your gut health, makes food easier to digest, prevents hypertension, and boosts your immune system. Other potential benefits include weight loss, mental health benefits, fighting cancer, and lowering the risk of heart disease. Japanese fermented food is actually really good for your health.

Shirley’s class is also very interactive and hands-on. After we make shoyu koji together, we are going to cook a full traditional Japanese meal. If you hear some barking in the background, that’s Colin, Shirley’s Chihuahua. She (yes, Colin is a girl), she is in the room next door and is dying to join us, I wish you could see her, she is so cute.

[Sounds of cooking] 

SHIRLEY: While we are doing this, I wanted to make one tofu dish. So, I need shirodashi and--. Here’s one typical dish. We use this for grinding. 

EMILIE: What is it called?

SHIRLEY: Suribachi. We break this sesame, sesame seeds. You’re going to use one tablespoon and we’re going to crush it with this bowl. Can you hear it?

EMILIE: What sound does it make?

SHIRLEY: Pichi-pichi (laughs). Oh, it smells great.

EMILIE: Yes, it smells good. It’s the traditional way.

SHIRLEY: Yes, this is the traditional way. And let’s add this Shirodashi. Actually, Shirodashi is a soup stock with soy sauce and mirin and a little bit of koji. It’s a mixture. 

EMILIE: And with Shirley, every ingredient is a learning opportunity. 

SHIRLEY: I forgot to tell you, soy sauce is also a fermented seasoning. There are many kinds of soy sauce. This is the original one. At Japanese kitchen, we also have this light soy sauce. The color is a little bit lighter, so if you want a lighter-colored dish, we use this light soy sauce. 

EMILIE: But is the flavor less stronger than the normal soy sauce.

SHIRLEY: No, the fermentation time is shorter so it’s much more saltier.

EMILIE: Here’s Shirley again, mashing the tofu.

SHIRLEY: This is called shiro-ae. Shiro is white and mixed with veggie, so it’s called “shiro-ae”. And it becomes one of the dishes of ichi jiu san sai

EMILIE: Ichi jiu san sai is the traditional Japanese meal layout, it literally translates to one soup, 3 dishes. The main dish usually consists of protein, such as fish, meat, or even eggs. The two other side dishes are veggie-based, that can be beans, potatoes, mushrooms or even tofu . Ichi jiu san sai also comes with rice, miso soup and pickles. There are at least two fermented foods in that set.

Japan is proud of its traditions, and food culture is no exception. Ichi jiu san sai is served in every ryokan, the Japanese inn as a traditional breakfast. And even as the years goes by, these traditions have stayed the same; that goes for fermented food, too. Historically, no one really knows when the first fermented foods were consumed, some experts say that it could go back to 4000 years ago. What’s sure though, is that Japan’s humidity and hot summer temperatures are favorable to fermentation, and in the past, Japanese people needed preserved food to survive.

SHIRLEY: My grand-grandmother was making it so it was handover from generation to generation.

EMILIE: So how did your grand-grandmother make fermented food? How did she do?

SHIRLEY: Actually the same way. Yes, like miso. I think they were making soy sauce as well. For now, I don’t make soy sauce so I can’t really tell but miso is the same way, using koji, salt and soybean. Older people use pot to put in to ferment, but nowadays you can use plastic, which is not very good but it’s been more convenient to make.

EMILIE: Do you think fermented food is going to be more and more important for Japanese people?

SHIRLEY: Not only for Japanese people, but from people around the world. Because all have a gut which controls your whole body. You are made from what you are eating.

EMILIE: Even with many years under its belt, fermented foods like soy sauce, miso, and yes, natto too, are still at home in Japanese pantries And the fuss has even spread overseas, ever since the efficacy of fermented food on gut health has come to light. So if you are tired of kombucha switch to miso soup! Just for you, here is Shirley with her secret recipe.

EMILIE: So how do you do the miso soup?

SHIRLEY: First make a soup stock with bonito fish and kombu. And then add any ingredients to the soups and today we are going to use wakame, wakame which is a seaweed. Very typical ingredients for miso soup. And about one cup of soup, you need about two tablespoons or a little less, it really depends on the miso. Saltiness is different, so I can’t tell how much. Let’s try. If it’s too salty, you can just add hot water to it. Is it okay?

EMILIE: It’s very good.

SHIRLEY: Thank you.

EMILIE: Want to hear more from Shirley? Join her fermentation classes: the Cooking with Koji Class in Tokyo, or the Miso Making Class with Miso Tasting. Both classes can be booked on the byFood platform. 

[Outro Music]

EMILIE: This show is reported, produced and audio edited by me, your host, Emilie Lauer. Our editor is Rika Hoffman. Tabesugi is executive produced by Serkan Toso of, the one-stop platform for foodie travelers in Japan. If you are interested in food experiences like food tours, cooking classes, tastings, and dining experiences, check out, that’s B-Y-F-O-O-D dot com.

Stomach growling? Browse food experiences in Japan or check out our YouTube channel!

We strive to be as accurate as possible and keep up with the changing landscape of Japan's food and travel industries. If you spot any inaccuracies, please send a report.
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