Natto (fermented soybeans) is an amazing food. It’s not necessarily the easiest for the uninitiated to approach and love; it has a unique taste and an incredibly unusual texture (I say “slippery,” detractors might say “slimy”). I grew up eating the stuff from a very young age, and love it very dearly. It has many flavor components in common with aged cheese and miso: savory, nutty, lots of that good umami.
It’s very good for you too, absolutely crammed with probiotics, K2 and lots of other goodies that have been linked to cancer prevention, bone health, heart health and skin benefits. Because the bacteria culture (bacillum subtilis) gets a chance to break down the mostly indigestible soy by means of fermentation, this traditional method* renders the humble soybean into a nutritional powerhouse.
*Speaking of traditional methods. If you were to do this the “original” way, you would leave cooked soybeans wrapped in rice straw next to a wood fire for several days, but that’s a bit loosey-goosey for my tastes.
HOW TO MAKE NATTO
* you can forgo the pressure cooker if you feel like boiling beans for 3 hours.
*(I know it’s daunting if you don’t read Japanese…but look for the Japanese organic seal on the package, order organic natto online [a little pricier], or buy yourself a powdered starter from the amazing and glorious GEM Cultures company [local to the NW!])
– Soak 2 cups of dried soybeans overnight in a big glass container with 6 cups of water to completely cover the beans, plus another inch or so. Cover. They will swell up to about three times their original size. Refrigerate if you like, I haven’t found it necessary.
– The next day, the soybeans have to be cooked. You can steam / boil them, but this takes a reeeally long time (5 hours or so) and boiling them leaches a lot of the nutrients and taste out. A pressure cooker is the best way to go. I pressure cook my beans (following the manufacturer’s instruction for safety and all that jazz) for 18 minutes, then remove the cooker from the heat. I let them sit for another 15 minutes or so, a little beyond the time where it is safe to remove the lid from the cooker.
– Drain the beans, there’s no need to let them cool any further. Heat stimulates the bacteria added in the next step.
– Mix your starter natto with about ½ cup of boiling water. It can be a styrofoam package from the store, the equivalent amount from your last batch, or the recommended amount of powdered starter. Don’t worry about killing the bacteria; the heat wakes them up from their refrigerated slumber!
– In a large, shallow glass baking pan, mix the drained beans with the natto starter. (Since most natto comes frozen, I leave this package in the fridge the night before so that it’s ready to go.) Mix in well, and smooth the beans into an even layer at the bottom of the pan.
– Wrap the top of the pan with aluminum foil, and poke holes all over it (and a generous amount, too). This allows the oxygen to help feed the bacteria that makes natto.
– The natto must now be kept at 100-110 degrees even for 24 hours, with a little bit of humidity. There are a few ways that you can do this; with a heating pad, in a big cooler with bottles of hot water, in a low heat oven (make sure to monitor the temp carefully), or a dehydrator – the easiest method as long as you don’t mind your apartment smelling like socks for a few hours, and checking in to make sure the beans aren’t drying out. I really recommend getting a remote / cord oven thermometer so you can check temperatures without having to open any contraptions you’re using and lose heat.
– After 24 hours, the natto should smell weird (and weirder than usual; I balked when I first smelled the hot metal and foot funk combo – and I’ve been eating this stuff since I was a baby) and whitish cultures may be developing on the beans. The stickiness should be in full effect too. The smell, I should point out, will be strongly ammonia, and the aluminum might produce an unpleasant metallic scent on top of that. If anything smells actually rotten or decaying, or there are weird colors…it is better to err on the side of caution. Testing small batches, like one bean at a time, is the way to do it.*
– This batch should then be aged in the fridge for 3 days to achieve the best flavor. You can eat it straight out of the oven (and why not try it!) if you want, but I’d recommend the waiting period. Give it a stir if you see the beans drying out on top, or a sprinkle of water if you like. Make sure not to make it too watery, because that’s gross and really hard to undo.
(*If you’re extremely new to natto, I would certainly advise buying a packet of it to try out before investing time, energy and money into making it. If not to see what it should look / taste / smell like, than at least to decide if it’s something you’d like to eat! Remember that commercial natto beans will be a lot more small and shriveled and brown than your robust home-soaked ones!)
HOW TO EAT NATTO
If you’re starting off by swimming in the shallow end, I think one of the easiest ways to enjoy natto is in a sushi roll. If you’re not good with a rolling mat, make yourself a hand roll! The tart sushi rice, the nori and some shoyu (soy sauce) take the flavors to a really nice place.
If you’re feeling squirmy about about the texture, throwing some into a batch of fried rice works really nicely. I like short grained rice, myself, and I think natto with long-grain would be kind of foul.
Serving a spoonful into a hearty bowl of miso soup is also a really easy way to ease into the sliminess – it all but disappears and you’ve got a nice enriched soup on your hands. I like to fancy up my miso with sliced shiitake mushrooms and chopped mini-greens (like mitsuba, parsley or shiso)!
The “traditional” way to eat natto is whip it up real foamy (yup, seriously) with a splash of soy sauce, a little Japanese mustard, some scallions and eat it over white rice, sometimes with a raw egg.