What Is Natto? Japan's Sticky Fermented Soybean Food Explained

Published: 2026-09-17 / Updated: 2026-10-16 ・ 5 min read

What Is Natto?

Natto (納豆) is a traditional Japanese food made from soybeans fermented with a specific bacterium called Bacillus subtilis, which gives it a distinctively sticky, stringy texture and a strong, pungent smell. It is most often eaten at breakfast, spooned over a bowl of hot white rice, and it's one of the first foods overseas visitors ask about simply because of how different it is from anything in Western cuisine.

Natto has been part of Japanese food culture for centuries, and today it's sold in nearly every convenience store and supermarket in the country, usually packaged in small plastic containers of two or three servings. For a first-time visitor, understanding what natto actually is — and how locals eat it — makes it much easier to decide whether to try it, and how to enjoy it if you do.

How Is Natto Made?

Natto starts with whole soybeans, which are soaked, steamed, and then inoculated with Bacillus subtilis spores (often called "natto bacteria" in Japanese, 納豆菌). The beans are left to ferment for roughly a day in a warm, humid environment, during which the bacteria break down proteins in the soybeans and produce the sticky, web-like strings that natto is famous for. After fermentation, the natto is typically chilled before being packaged and sold.

This fermentation process is similar in spirit to how other fermented foods like cheese or yogurt are made, though the bacteria and flavor profile are completely different. The result is a food that's soft, slightly mushy, and covered in thin, glue-like strands that stretch when you lift a spoonful.

What Does Natto Taste Like?

This is one of the most common questions from visitors, since the smell often arrives before the taste. Natto has a strong, somewhat sharp aroma that some compare to aged cheese or ammonia, which can be off-putting at first encounter. The actual flavor underneath, however, is milder: earthy, nutty, and savory, with a natural umami quality typical of fermented soy products.

Texture is arguably the bigger hurdle for newcomers. The beans are soft and slightly slippery, and the sticky strings cling to chopsticks, the rice bowl, and sometimes your lips. Stirring natto vigorously before eating is actually the traditional method, as it's believed to improve both texture and flavor — so don't be shy about mixing it well.

How Do Japanese People Eat Natto?

Natto is most commonly eaten as part of a traditional Japanese breakfast, poured over a bowl of plain steamed rice. Most store-bought packs come with two small sachets: one containing a soy-sauce-based seasoning (tare, たれ) and the other containing Japanese mustard (karashi, からし). Diners typically mix both into the natto before stirring everything together with chopsticks and spooning it over rice.

Beyond the classic rice-topping style, natto appears in a few other common forms:

• Natto maki — a type of sushi roll with natto wrapped in nori seaweed and rice, found at sushi restaurants and conveyor-belt sushi chains.
• Natto with egg — mixed with a raw or soft-cooked egg for extra richness, sometimes as part of a dish called tamago kake gohan variation.
• Natto soba or udon — stirred into cold noodle dishes, especially in warmer months.
• Natto toast — a more modern, casual twist found in some cafés, combining natto with cheese on toasted bread.

Regional preferences do exist. Eastern Japan, including Tokyo and the greater Kanto region, has historically eaten more natto than western Japan, where some areas have traditionally been less enthusiastic about it. That said, it's now sold nationwide and increasingly popular even in regions that once consumed less of it.

Why Does Natto Smell So Strong?

Natto's smell comes directly from the fermentation process and the metabolic byproducts created by Bacillus subtilis as it breaks down the soybeans. This is a natural result of fermentation, similar to how blue cheese or kimchi develop strong aromas through their own bacterial or fungal processes. The smell is generally stronger than the taste, which is why many visitors find natto easier to handle than they expected once they actually try it.

Common Mistakes First-Time Visitors Make

A few small missteps can make the natto experience less enjoyable than it should be:

1. Not stirring enough. Giving the natto only a quick stir leaves it less creamy and can make the smell seem stronger. A more thorough stir (locals often recommend dozens of strokes) smooths out the texture.
2. Skipping the seasoning packets. The tare sauce and mustard are designed to balance natto's strong flavor, so using them as intended usually gives a more approachable result than eating it plain.
3. Expecting it to taste like the smell. Many visitors brace for an overwhelming flavor based on the aroma alone, then find the actual taste much milder than anticipated.
4. Not checking for soy allergies. Natto is made entirely from soybeans, a major food allergen. Travelers with soy allergies should avoid it, and anyone uncertain should check ingredient labels or ask staff when ordering dishes that may contain it.

Where to Find Natto in Japan

Natto is sold at virtually every convenience store and supermarket across the country, usually in the refrigerated section near other soy products like tofu. It's also a frequent feature of Japanese-style breakfast sets at hotels and traditional inns (ryokan), often served alongside rice, miso soup, grilled fish, and pickles. Because it's a refrigerated, fermented product, it should be kept chilled and eaten by the expiration date printed on the pack.

For visitors curious about the nutritional side of soybean-based foods like natto, it's worth checking official resources such as the MEXT Food Composition Database, which provides detailed nutritional breakdowns of Japanese foods, or browsing this site's dedicated nutrition pages for more context.

Final Thoughts

Natto is a genuinely unique part of Japanese food culture: a fermented soybean dish defined by its sticky texture, strong aroma, and savory depth. Whether or not it becomes a favorite, trying a small pack over rice — stirred well, with the included seasonings — is the most authentic way to experience it the way most Japanese households do every morning. For general travel planning and food experiences across Japan, the Japan National Tourism Organization offers further background on regional specialties worth exploring during a visit.

FAQ

Q. What does natto taste like?

A. Natto has an earthy, slightly nutty, umami-rich flavor with a sharp, cheese-like or ammonia-like smell that is much stronger than its taste. Texture matters as much as taste here: the sticky, stringy strands surprise many first-time eaters more than the flavor itself.

Q. Is natto healthy?

A. Natto is a soybean-based fermented food and a source of plant protein, but this article does not make specific health claims. For detailed nutritional data, check the [MEXT Food Composition Database](https://fooddb.mext.go.jp/) or this site's nutrition pages.

Q. Where can visitors try natto in Japan?

A. Natto is sold in small plastic packs at almost every convenience store and supermarket across Japan, and it's commonly served at breakfast in hotels offering a Japanese-style morning set.