Ingredient

Natto

Natto is whole soya beans fermented by a bacterium into something sticky, stringy, powerfully savoury and strongly smelling. It is a Japanese breakfast food, it is one of the most divisive foods in the world, and almost everything people find alarming about it is the intended result rather than a sign of spoilage.

What it is

Cooked soya beans are inoculated with Bacillus subtilis var. natto and held warm for about a day. The bacterium works on the beans and produces two things that define the food: a great deal of glutamate, which is why it tastes so intensely savoury, and a polymer coating the beans in long sticky threads.

The threads are the famous part. Stir natto and it draws out into fine strands that follow the chopsticks halfway across the room. The stickiness is not a texture accident — it is a polymer the bacterium makes, and the amount of it is a quality marker in Japan rather than a defect.

The smell is ammoniac and cheesy and arrives before anything else. It is the same family of aroma as a very ripe washed-rind cheese, which is the most useful comparison for anyone deciding whether to try it.

How it is actually eaten

There is a standard way, it is not complicated, and doing it properly makes an enormous difference to how the food comes across.

1. Open the pack. Most sell with two sachets tucked on top — a soy-based sauce (tare) and a little mustard (karashi). Take them out before you do anything.
2. Stir the beans on their own, hard, for a while. Thirty to fifty strokes is the usual advice. The threads develop and thicken as you go, and this genuinely changes the texture from loose beans to a cohesive mass.
3. Add the sauce and mustard, and stir again to combine.
4. Spoon it over hot rice. The heat of the rice loosens it and softens the smell.
5. Add a raw or soft egg yolk, chopped spring onion, or shredded nori if you like — all three are standard and all three make it easier for a newcomer.
6. Eat it with the rice rather than on its own. Natto by the spoonful is a much bigger ask than natto as a topping.

Other ways it is used

• In miso soup, stirred in at the end, where it disperses and the stringiness largely disappears.
• Folded into an omelette, which mutes both the texture and the smell considerably.
• On toast with cheese, which is a modern Japanese home cooking staple and works on exactly the same logic as any strong cheese on toast.
• In fried rice or with noodles, where it behaves as a savoury binder.
• As natto maki, rolled in sushi with nori and rice.
• Frozen. Natto freezes and thaws well, so a pack bought and disliked can wait, and packs are commonly sold frozen anyway.

If you have never had it

The honest advice is to manage three things separately, because they are three separate obstacles and people usually collapse them into one.

The smell is the first and it is front-loaded. Serving it over hot rice with spring onion and nori covers a surprising amount of it.

The texture is the one most people actually struggle with, and stirring properly helps rather than hurting — a well-stirred natto is cohesive and manageable, while an unstirred one is loose beans in slime, which is much worse.

The flavour, once you are past the other two, is not difficult at all: deeply savoury, faintly bitter, a bit like a strong cheese. Plenty of people who expect to hate natto find that the taste is the easy part.

Start with a small amount over a large bowl of rice, with the sauce, the mustard and something sharp. That is how it is eaten, and eating it the way it is eaten is a better test than eating it plain.

The three fermented soya beans, told apart

They come from the same bean and are not remotely alike.

Natto

Whole beans, bacterial fermentation, sticky and stringy, powerfully savoury and pungent. Eaten as it is, over rice. Japanese.

Tempeh

Whole beans, mould fermentation, bound into a firm dry cake. Nutty and mild. Cooked before eating. Indonesian.

Miso and doenjang

Beans fermented with grain and salt over months into a paste. Deeply savoury, used as a seasoning rather than eaten alone. Japanese and Korean respectively.

Tofu

Not fermented at all. Soya milk curdled and pressed. Neutral and soft.

Common questions