What Is Natto? Japan's Fermented Soybeans Explained
Key takeaways
- Natto is soybeans fermented with Bacillus subtilis, giving it a sticky, stringy texture and a strong, distinctive smell.
- It's most commonly eaten at breakfast over rice, mixed with soy sauce, mustard, and often raw egg or green onion.
- Natto contains soy, one of Japan's common allergens, so check labels if you have a soy allergy or sensitivity.
What Is Natto?
Natto (納豆) is a traditional Japanese food made from soybeans that have been fermented with a bacterium called Bacillus subtilis. The fermentation process gives natto its two most recognizable features: a sticky, stringy texture that pulls into thin threads when stirred, and a strong, distinctive smell that some describe as pungent or cheese-like. It is most commonly eaten at breakfast, spooned over hot rice, though it also appears in other dishes across the country.
For visitors trying Japanese food for the first time, natto is often one of the more surprising items on the table. It looks unlike almost anything in Western cuisine, and the smell and texture can take some getting used to. At the same time, it is an everyday food for many households in Japan, sold in nearly every supermarket and convenience store, usually in small foam containers of two or three servings.
How Natto Is Made
Natto starts with whole soybeans, which are soaked, steamed or boiled until soft, and then mixed with a starter culture containing Bacillus subtilis spores. The beans are packed into containers and left to ferment for roughly a day at a warm temperature, followed by a period of cooling and maturing in a refrigerator. During fermentation, the bacteria break down proteins in the soybeans, which is what creates the sticky, stringy coating and the food's characteristic aroma.
This basic method has been used in Japan for centuries, though the packaging and commercial production seen today are modern. Natto is produced in many regions of the country, with some areas, particularly in eastern Japan, historically associated with especially strong natto consumption and production.
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Natto consists of whole, softened soybeans held together by a slippery, sticky coating. When stirred with chopsticks, this coating stretches into long strings, which is part of the eating experience and not a sign that anything is wrong with the product. The smell is often the first thing newcomers notice: it is strong and can be described as similar to strong cheese, ammonia, or fermented foods in general. The flavor itself is milder than the smell suggests, often described as nutty, faintly sweet, and slightly bitter, with a savory depth from the fermentation.
Texture is usually the bigger hurdle for first-time eaters, more so than the taste. The combination of soft beans and sticky strings is unlike most Western foods, so it can take a few tries before the texture feels normal.
How to Eat Natto
Natto is almost always sold with small packets of seasoning included: a soy sauce-based sauce (called tare) and a small amount of Japanese mustard (karashi). The typical way to eat it, in three basic steps, is as follows:
1. Stir the natto first, before adding anything else. Stirring it around 20 to 30 times with chopsticks is a common approach, though there's no fixed rule; this step is meant to develop the sticky texture further and mix the beans evenly.
2. Add the seasoning packets, tearing open the soy sauce-based tare and the mustard, then stirring again to combine everything.
3. Serve over hot rice, either mixed in a separate small bowl and then poured over rice, or added directly on top of a bowl of rice and eaten together with a spoon or chopsticks.
Common additions include a raw egg (sometimes just the yolk) stirred in for extra richness, chopped green onion, grated dried bonito flakes (katsuobushi), or a small amount of Japanese mustard beyond what's included. Natto is also used in other dishes, such as natto maki (a sushi roll filled with natto), on top of okonomiyaki, mixed into miso soup in some regional styles, or paired with other ingredients like sliced okra, which is also sticky in texture.
There is no single "correct" way to eat natto beyond the basic soy sauce and mustard approach; many households and individuals adjust it to their own taste.
When and Where Natto Is Eaten
Natto appears most often at breakfast, as part of a traditional Japanese breakfast set alongside rice, miso soup, grilled fish, and pickles. This kind of breakfast is served at many Japanese-style inns (ryokan) and some hotels, so visitors staying at a ryokan may encounter natto on the breakfast tray even if they haven't sought it out. It is also eaten at other times of day and is a common convenience-store and supermarket item nationwide, typically sold in packs of two or three small containers for a few hundred yen, though prices vary by region and retailer and can change over time.
Regional Differences and Variations
While natto is eaten throughout Japan, it has historically been more prevalent in eastern Japan, including the greater Tokyo area and the Tohoku region, compared to some western areas, though it is now widely available and consumed nationwide. Some regions have their own traditional variations, such as natto made with larger or smaller soybeans, or dishes that incorporate natto into soups, rice bowls, or noodle toppings.
Visitors interested in trying regional food traditions can look for natto served as part of a set breakfast at accommodations that offer Japanese-style meals, though this is not guaranteed at every property and it's worth checking meal details when booking.
Common Questions and Mistakes
First-time eaters sometimes make a few common mistakes. Eating natto without stirring it first is one; the beans and sauce blend more evenly when stirred, and skipping this step can leave the seasoning unevenly distributed. Another is judging natto by smell alone before tasting it, since the flavor is generally milder than the aroma suggests. Some visitors also expect natto to be served warm or cooked, when in fact it is eaten cold or at room temperature as a fermented, ready-to-eat food.
Because natto is made from soybeans, it contains soy, which is one of the allergens commonly labeled on packaged food in Japan. Travelers with a soy allergy or sensitivity should check ingredient labels or ask about ingredients when dining out, since natto or soy-based derivatives can appear in other dishes as well.
Where to Learn More
For general information about Japanese food culture and travel in Japan, the Japan National Tourism Organization is a useful official resource. For questions about food composition, nutrition figures, or ingredient standards in Japan, the MEXT Food Composition Database and the Ministry of Agriculture, Forestry and Fisheries provide official data and background. Readers interested in the nutritional content of natto and other soy-based foods can also check the nutrition section of this site for more detail.
FAQ
- Q. What does natto taste like?
- A. Natto has a strong, earthy, slightly pungent smell and a savory, faintly bitter flavor. Its texture is soft and sticky, with long strings that pull when disturbed, which is more noticeable to first-time tasters than the taste itself.
- Q. Is natto eaten raw or cooked?
- A. Natto is not cooked before eating; it is a fermented, ready-to-eat food. It can be served cold or at room temperature, often stirred first, and is sometimes lightly warmed on top of hot rice.
- Q. Why do some people dislike natto?
- A. The sticky, stringy texture and strong smell are unfamiliar to many first-time visitors, even though natto is a common, everyday food for many people in Japan, especially at breakfast.
