Daisuke Iwase spends more than twelve hours a week sorting soybeans by hand. That happens in a small workshop at 57B Glebe Point Road, a few kilometres from our Leichhardt store, and it is the first step in a five-day process that ends with a paper tub of natto in our fridge.
Natto is one of those foods people have strong opinions about before they have tried it. Sticky, stringy, with a smell that gets described in unflattering ways. Most of what puts people off, though, is old or badly handled natto, and Dai's business started from exactly that frustration. Here is what natto is, how he makes it, how to eat it for the first time, and how to pick between his small-bean and large-bean tubs, fresh and frozen.
A dance teacher, a pandemic and spores from Tokyo
Dai's Natto was established in May 2021. Its founder, Daisuke Iwase, was born in Hiroshima, lives in Sydney and still teaches dance part-time. Before the business existed he was buying frozen natto imported from Japan and was not happy with it. "The fresh natto you get in Japan doesn't have a smell," he told SBS Food. "Some frozen natto can smell like ammonia."
During COVID he started experimenting at home with natto spores sourced from Tokyo. That turned into what the company calls Sydney's first natto workshop, in Glebe, and SBS describes him as the first Sydneysider to offer locally made natto on a commercial basis. It is a small, owner-operated business that now supplies Japanese grocers around Sydney, stockists in Melbourne and Queensland, and us.
What natto is
Natto is whole soybeans that have been steamed and then fermented by a bacterium, Bacillus subtilis var. natto. It is most popular in eastern Japan (Kanto, Tohoku and Hokkaido) and eaten far less in Kansai. Traditionally the cooked beans were wrapped in rice straw, which carries the bacterium naturally; in the Taisho period (1912 to 1926) researchers isolated a pure starter culture, and straw was no longer needed.
Three things follow from that. Natto is not raw: the beans are fully cooked before the culture goes in. It is unsalted, which separates it from miso (a koji ferment made with salt) and tempeh (a mould ferment pressed into a cake). And the stickiness, the neba-neba, is mostly a polymer called poly-gamma-glutamic acid that the bacterium secretes, which stretches into long elastic threads when you stir it.
How Dai makes it in Glebe
The beans are all Australian, and there are two lines. Kotsubu, the small bean, is made from non-GMO soybeans grown in Queensland. Chu/Ootsubu, the medium-to-large bean, is made from organic soybeans grown in New South Wales. The only other ingredient is a natto starter imported from Japan. On the organic tubs the ingredient panel reads, in full, "Australian organic soybean, Japanese natto starter."
The process, as he described it to SBS, starts with that hand sorting. The beans are soaked, for a time that shifts with the season, pressure-steamed for hours, and inoculated with the spores while still hot. Japanese industry guidance puts that at around 70 to 90 °C: the spores survive the heat and most contaminants do not. Then comes an initial fermentation, followed by what Dai calls a secondary slow fermentation to build umami. Our listing puts the whole thing at about five days. The tubs are paper and the wraps are biodegradable.
To be clear on the organic question: the Chu/Ootsubu line is made with Australian organic soybeans, but we have not found a certifier's mark on the finished natto, so we do not call it certified organic. The Kotsubu line is non-GMO rather than organic.
Why natto smells, and why fresh smells less
The smell comes from the fermentation itself. Pyrazines and diacetyl give the nutty, savoury part, and branched fatty acids such as isovaleric acid give the cheesy note. Ammonia, the sharp part people object to, comes from protein breakdown and builds up when natto is over-fermented or old. Fresh, well-made natto has very little of it, which was Dai's point about imported frozen tubs.
The culture does not stop working in the fridge. Dai's FAQ says the spores become active above 10 °C, and that fresh natto ferments slowly even when chilled, with the umami increasing as the days go by. A tub at day ten tastes deeper than one at day two. Past the best-before date the ammonia builds, and the flavour goes with it.
How to eat natto for the first time
The classic way, and the one to start with, is over hot rice at breakfast: natto gohan. Take the tub out of the fridge and stir the natto with chopsticks before you add anything. Ten to twenty stirs is enough to get it fluffy and sticky; the traditional advice is forty or fifty, and the often-quoted 424 is folklore rather than a method.
Then add the seasoning: soy sauce or tamari, a dab of karashi (hot Japanese mustard) and chopped spring onion, with the sauce going in over a couple of goes rather than all at once. Spoon it over the rice and eat it while the rice is hot and the natto is cold. If the taste is stronger than you would like, an egg yolk or a few drops of sesame oil soften it considerably, and mayonnaise is popular with children in Japan for the same reason.
From there the toppings are open: kimchi, sliced okra, grated nagaimo, shredded nori, katsuobushi, avocado, grated daikon, and Marukome notes it goes well with parmesan, olive oil and chilli oil. Natto also turns up in maki rolls, miso soup, omelettes and pasta. Heating it flattens the fluffy texture and strengthens the smell, so add it to a hot dish at the end. A 2009 survey of 3,827 people in Japan found 70 per cent liked the taste, so three in ten Japanese people are not keen either.
Which tub: Kotsubu, Chu/Ootsubu, fresh or frozen
Natto in Japan is classified by bean size, from large (ootsubu) through medium (chutsubu) to small (kotsubu). Dai makes two. Kotsubu 70g is the small bean, the Japanese default. Small beans are close to the size of a rice grain so they mix into a bowl evenly, and more surface area per gram means more of the sticky paste and more flavour. If you are new to natto, start here. It is $6.20, and the Kotsubu 220g tub is $17.45 for households that get through it.
Chu/Ootsubu 70g is the medium-to-large bean, made with the NSW organic soybeans, at $6.10. Larger beans are chewier, with a stronger soybean flavour, and they hold up eaten on their own or in cooked dishes rather than disappearing into rice. The Chu/Ootsubu 220g is $17.45. With the big tubs, use clean utensils each time and press cling wrap onto the surface so it does not dry out.
The fresh tubs have a 16-day shelf life from production and live in the fridge. If you are eating natto this week, they are the ones to buy. The Frozen Organic Natto Chu/Ootsubu 80g is the same organic large-bean natto frozen, with a 180-day shelf life at −18 °C, at $5.99, and it is the one to keep for the weeks when you have not been to the shop. Thaw it in the fridge for about half a day or overnight, never in the microwave, then eat it within a few days and do not refreeze.
Everything here contains soy, and Dai's own FAQ says it is not recommended for anyone with a soy allergy. All of it is made from two ingredients, so it is vegan. Gluten depends on the sauce you add: use tamari rather than regular soy sauce if that matters. The whole range is on our Dai's Natto collection.
Questions people ask
What is the white stuff on my natto?
A thin white film across the surface is the bacterial film from fermentation, normal and edible. Small white gritty specks are crystals of an amino acid called tyrosine, which form as fermentation goes on. They are harmless, a little crunchy and slightly bitter, and a sign the tub is getting on. Neither is mould.
How long does fresh natto keep?
Dai gives 16 days from production. It keeps fermenting slowly in the fridge and the flavour deepens. If it smells strongly of ammonia, it is past its best.
Can I make natto at home?
Yes, with a starter culture and something that will hold about 40 °C for 22 to 24 hours after the beans are soaked and pressure-cooked. Holding the temperature is fiddly and over-fermenting is easy, which is why a workshop that does nothing else is a reasonable thing to pay six dollars for.
Dai's fresh and frozen natto is in the fridges and freezers at Leichhardt and Crows Nest, and you can order it online for home delivery across Sydney. Start with a small tub of Kotsubu and a bowl of hot rice.
