Is it easy to start a natto culture? To perpetuate one?

April 12, 2017 11:29 AM

So I'm down to probably about 50 lbs of soy beans, and having recently found and tried natto, really like it! So I'd like some natto-culturing advice.

I've found a Canadian company that sells natto culture, but I'm not sure (a) how difficult it is, (b) if I should be looking at any special equipment [apparently heat is an issue], and (c) if, once I've started a culture, I can just perpetuate more natto yogurt-style, or if I'm going to have to keep buying cultures every time I want to make more natto.

Any natto advice is welcome!

posted by Shepherd to Food & Drink (5 answers total)

In Canada my wife made it from scratch in the oven for a while, but gave up because it's too labour-intensive. I think you could use a rice cooker or slow cooker rather than the oven; we need our rice cooker to make rice every day.

I don't know about reusing natto in perpetuity. Everything I've read indicates you need to buy spores each time you want to make natto.
posted by My Dad at 11:48 AM on April 12, 2017

Making natto isn't difficult! It can be labor-intensive, though.

I've made natto with both the spores and from packaged (frozen) natto from Japan. The natto that came from the spores was definitely less gooey-- it was okay, but I find super gooey natto a lot more satisfying. Theoretically you could keep making it from your own supply, but I've always been freaked out that this would lead to some sort of contamination. (Before I started making it, I was sort of under the impression that natto could never go bad. I was mistaken.)

Special equipment isn't necessary, but you might need to play around to get the right mix of heat and dryness. My first failure was when I used a bunch of glass yogurt containers-- it was too wet. For awhile I was successfully making huge quantities of natto by wrapping steamed, inoculated soybeans in parchment paper and keeping the packets wrapped in a Japanese electric blanket on high for two days-- this seemed to allow water to escape while keeping the heat sufficiently high.

Steaming soybeans for hours is a pain, though. I recently graduated to using an Instant Pot to both steam and ferment-- you can use the pressure cooker setting for the first part, and the yogurt setting for the last part. I'm happy to report that it works and it's a lot less mess and cleanup.
posted by naturalnumbers at 12:18 PM on April 12, 2017 [1 favorite]

Best answer: I make natto regularly. It's pretty easy. I have never done it using purchased natto culture (or natto-moto). Instead, I just go to the local Japanese store and buy a package of natto. It is full of active bacteria that, when mixed with cooked soybeans, will wake back up and continue to do their thing.

If I am on top of my planning game, I will freeze some of my batch and use it as the starter for next time. I've kept it frozen for months (like 6 months) and it wakes up fine and happy. If not, I just go back to the store and buy another package.

You will need some way to maintain something like a bread-proofing temperature for up to 48 hours. Instant Pot is great and Canadian. I've used a Slow Cooker plugged into a temperature controller, and also just an electric heating pad from a drug store that I placed underneath the glass baking dish holding the soy beans.
posted by hammurderer at 1:41 PM on April 12, 2017 [1 favorite]

Response by poster: Our culture has arrived! I will be Instant Potting up some natto this weekend!
posted by Shepherd at 6:27 AM on May 1, 2017 [1 favorite]

Response by poster: It turned out really well!

Pressure-cooked soybeans & natto culture, 20 hours in the Instant Pot on the yogurt setting. Turned out beautifully, froze some to make more down the line.
posted by Shepherd at 4:15 PM on May 15, 2017 [1 favorite]