Wednesday, May 15, 2013

Homemade Natto Using Packaged Natto -Batch #37



Preparation:
Day 0, 9pm  or  Day 1, 730am
-400gr Kotsubu Laura's Soybean 16-20 hour soak, summer time 25C (77F). 20-24 hour soak, winter time 10C (50F).
Note: I prefer longer soaks over short soaks. So even in the summer, my tendency will be to soak it the night before even if I am steaming the soybeans the next day in the evening.



Day 1, 630pm
-Place beans in strainer and discard hard beans.
-Set up pressure cooker with water and place ramekin/small plate in the pot.
-Once boiling, put soybeans into strainer and place on top of ramekin inside the pressure cooker so the beans are not touching the water.





-Close lid on pressure cooker and build pressure. (My pressure cooker starts to whistle, at 1.5 bars or ~21 psi).
-After it builds pressure, set timer to 40 mins and lower range temp to medium-low. The Taylor thermometer is really handy as a timer and as a thermometer.



-While cooking, set oven temp 95-108F (34-42C avg 38) with a heat source (yutanpo, lamps, pre-heat, etc). In my case I use a 150W Ceramic Infrared Heat Emitter (plus a socket power plug) connected to a Digital Controller Thermostat
Note: Due to fire safety reasons, use at your own risk.



Alternatively, you can use a single coil cooking range (like this one) inside on the very bottom set to warm, and plugging it to a Digital Controller Thermostat
Note: Due to fire safety reasons, use at your own risk.

-Place a pot or soup plate with water on the bottom wire rack (for humidity) and leave the top wire rack empty to place the baking dish later.
-Sanitize baking dish for 20 mins with 1 TBL of chlorine and fill to the rim with water. Discard and rinse with water.

Note: Natto fans have suggested other sanitation methods such as Heat, Steam, and Sterisan. Please use the method that fits your needs.

-Also boil two spoons in a pot for 10 mins. Dump boiling water into the glass baking dish and discard water after 5 mins.  Alternatively, you can leave the two spoons in the baking dish that is sanitizing with chlorine. You will have to rinse with water afterwards so this is less sanitary. 
-When the 40 mins are up, place pressure cooker aside to cool for 20 min.






-After 20 min, open lid and put cooked soybeans into the glass baking dish. The soybeans should have turned from a pale yellow to a light caramel color.
-Put a cube of frozen packaged natto (1/9 th of a package, will work with 1/12th of a package or 6gr ~ 4gr, 5gr avg.) into the hot soybeans and make a little mound of hot soybeans on top to cover the natto with the sterile spoon. Wait a minute or two until frozen natto cube thaws.
Note: I usually keep the packaged natto in the freezer and cut it into 9 frozen cubes per 50gr pack which are kept in a zip lock bag for later batches. So a 3 pack (150gr) of Okame Natto frozen natto will yield 27 batches of natto!



-Mix the melted packaged natto with the sterile spoon and add 2-4 soup spoons (about ~2-4 measuring teaspoons) of the hot water from pressure cooker. Add enough while making sure it does not puddle on the bottom. Mix the soybeans, packaged soybeans and water with the sterile spoon until well incorporated. 
-Tightly wrap the cling wrap and poke holes with a tooth pick all over the surface of the cling wrap. Then, detach from edges and rest cling wrap on top of the soybeans.


Double Cling Wrap Method: One on top of soybeans, second one on the top tight on dish. Creates an air pocked in the middle slowing drying of soybeans. I poked holes on both wraps with a toothpick.

-Cut one more piece of cling wrap and wrap tightly on the baking dish and poke holes. This will form an air pocket that will maintain the moisture on the beans. Cool until it is luke warm and then place on the top rack of the oven.
-I will leave a soup plate or shallow pan with water on the rack below the natto dish to maintain moisture in the oven. Note: Shown in the pic below is a pot, which is too big and not needed.
-Leave the natto to ferment for 16 to 20 hours at 38C-42C (100F-108F)





Day 2, around 3 pm 
-Take out natto from oven and place at room temperature on the countertop. Cool before putting into fridge. You can leave to cool anywhere from 1 to 5 hours, I usually put it in the fridge after dinner or before going to sleep.



-Natto is finished fermenting! There should be a pleasant natto aroma with a slight hint of ammonia, but should not be overpowering. If eaten at this time, it will have a sharp taste. The threads should be thick, sticky and silky when pulled. They can be eaten at this time.


The threads should be thick, but should form really long threads when pulled.

-Refrigerate and let it rest for 3-5 days in which time the natto will become mellower and will deepen in flavor. It will keep in the fridge for up to 2 weeks. If there is still any left, they can be put in the freezer. Time to eat natto!
Note: After two weeks in the fridge, the natto will form animo acids crystals which are texturally a bit sandy akin of the crunchy bits in aged parmesan cheese. If the sandy texture is not desired, natto can be moved to the freezer  after about a week. 


Natto in its full glory

Natto should have silky threads that are thick when initially mixed. When made successfully, the threads will be silky even after adding liquid seasoning such as shoyu and mentsuyu. I also have made so-so natto which is silky, but looses its threads when shoyu is added. A few thoughts on this on a future post.



Note: Please use the "Contact Me" or email me directly at nattodad[at]gmail.com if you want direct replies.

20 comments:

  1. Thank you. Your blog has helped me make pretty good natto. I also had very little biofilm (neba neba) when I made natto from the spore, but I found that if I then extract the bacilus with hot water from a few natto beans from a previous batch (made also from the spore), the ‘neba neba’ increased drammatically. Also using containers that are hydrophobic like styrofoam, polypropylene, and wax paper seemed to help.

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  2. Love your blog!
    Question: if I make too many beans, more than I want to ferment at that time, can I put the excess beans in the freezer, and use them later to make natto?
    Meaning: defrost, reheat, mix natto starter with them, then let ferment per directions. Your opinion is valuable to me.

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    Replies
    1. Hi mz beastle, wow it took me while to reply. Hope your natto making is going well. I have not done this, but I do not see why this would not be possible. My two concerns would be contamination from the reheating and a defrosted texture of the soybeans. Please give it a try and let me know if you have any insights. Thank you for visiting the blog.

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    2. Well, I never did do the "frozen cooked" soybeans, because another natto lover said in all probability the freezing would destroy something in the bean, making it not acceptable to the natto bacillus.
      However, your information has helped me a LOT!
      My latest issue was using 3rd or 4th generation natto from my previous batches. For some reason, the finished product was not sticky. So, I broke out the store bought stuff as you suggested, made another batch, and it was out of this world neba neba! I mixed it with the barely sticky batch, and I consumed it. It was still delicious. And stringier!
      Thanks again for your great natto website resource.

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  3. I picked up a combo pressure cooker/yogurt maker and was hoping to start making natto by doing the pressure steam in an insert over water, followed by the fermentation with the yogurt setting (100 degrees F) in the main container. Given that this is a semi sealed container, do I still want to cover with wrap and leave semi open? ( I picked up the Instant Pot with Natto in mind)

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    Replies
    1. Thank you for reading the blog! To answer your question, you will know by looking at the surface of the finished natto. It sounds like you have a very nice setup so hopefully you will be able to use it as is. If the top layer looks drier it will be better to put a plastic wrap with holes right over the beans when you start the fermentation next time. You will know if the top layer dried because the beans will look darker or will become hard. In the most ideal condition, the top layer should look the same as the bottom layer.

      Hopefully that helps! Keep experimenting and best wishes on your 2016 natto making!

      Natto Dad

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  4. Welp, just to follow up the instant pot worked very nicely. Soak 300-350 grams beans Thursday morning in four cups of water, just drain them from soaker to mesh steamer insert Friday, and pressure steam for 45 minutes with a 20 minute cooldown in 1.5 cups water.

    Then 1) Boil bowl to hold steaming liquid, spoon for same, and wide paddle to stir with
    2) remove steamer, set aside, dump steaming liquid into ramekin, dump beans into Instant pot
    3) dump (lazy here) full package of store bought natto into pot, use paddle to stir and mix well with steamed beans
    4) add three tablespoons or so of the bean liquid
    5) and set the instant pot to yogurt setting for 24 hours.

    That sounds complicated but takes about 20 minutes in all. Finally Saturday morning, boil the lids, a couple spoons and paddles, and the first glass storage tray. Every 5 minutes remove the current tray to cool, drop the next tray in to boil, and load the cooled tray with 1/3 to 1/4 of the beans. Total time elapsed about 30 minutes but with lots of time for chores along the way.

    The output has been fine, three or four glass trays of four servings each. Let them rest in the refrigerator for two days, then freeze all but the next to be eaten.

    I'm not sure I'd bother without the pressure steamer/yogurt maker though. Having it all be one pot with minimal fuss is what beats the local market in Japantown San Francisco at three packages for USD 2.00.

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    Replies
    1. Thanks for the input! I am glad you found your groove with your setup. Natto on!

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  5. Hi Natto Dad, Thank you for your website, it has been a real help in making good natto.
    Although it has neba neba, there isn't as much as yours in the photo.
    Wondering about using store bought natto here in Australia as starter. As it is all from Japan, people here worry about it being contaminated with radiation.
    What are your thoughts? Do you know which brand of natto is safe? We use spores made in China.
    Thank you again for taking time to help us all.
    Mary Rose

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    Replies
    1. Hi Mary Rose,

      I totally missed your comment. For a direct reply please use my email written on the top right side of the blog page. I believe the cheaper brands use US/foreign grown soybeans so there should not be any radiation. The ones that are "Kokusan" using Japan grown soybeans mau be an issue. I have not clue how strict the radiation standards are in Japan. Hopefully they are strict enough the keep the Japanese population safe.

      I personally use Okame natto. It gives me the best nebaneba and it is super reliable. I believe it is one of the most common available too. I have used spore started but have never succeeded in making silky natto so my preference is towards the frozen natto.

      Hope that helps and sorry for the late reply.
      Natto Dad

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  6. Hello Natto Dad, yourwebsite is very helpful, i want to ask something, is it okay if i make natto with self-made styrofoam incubator? I used natto spore and it was very stingy and had thin string...

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    1. Hi Stepfany,

      Yes, I am sure you can use a styrofoam incubator. What is your heat source? Temperature is important so find a method that will give you 100F (~38C) for at least the first 12 hours. If possible for the entire duration of the fermentation ~20 hours. If available in your area, use frozen packaged natto as your starter. I have never produced a silky batch using spore starter. Need to work on it this winter.

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    2. Thank you for your reply, i'm very glad because i don't have an oven, i used 15watt lamp, and i had made sure the temperature around 40c

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    3. Thank you for your reply, i'm very glad because i don't have an oven, i used 15watt lamp, and i had made sure the temperature around 40c

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    4. My only concern would be to take extra precautions with the heat source so it does not touch the styrofoam. I am not sure how flammable styrofoam is but it never hurts to be on the safe side. Hope the ferm goes well and send me pics of your natto! If you need a direct response you can contact me at my email written on the top right of the page. Just out of curiosity, did you get a message when I replied to your comment or did you have to check back to my blog?

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    5. I checked back your blog, sure, i'll send you pics

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  7. Hey, Natto Dad, this blog is great! It helped a lot.

    I have a question: in your video you talk about that 4 days later is more sticky. This 4 days are continuin fermetation or ir the fridge o at room temperature?

    Thaks!

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    Replies
    1. Hi El Favricante, not sure if I had replie to this. So off from the fermentation, it goes into the fridge right away. I like hoe natto tastes between 4 days and a week and a half in the fridge. After two weeks, portion out and freeze. -Natto Dad

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  8. Hi Natto Dad,

    Received my Mitoku starter in the mail today (before I found your blog, ugh!) and am about to set out on my first natto-deavor. A couple of questions for you (apologies if you've already answered some variation of them):

    1) Is it necessary to soak your beans if you intend to pressure cook them?

    2) Have you ever used something like a sous vide (water bath) to keep the temperature precise? This would involve sealing the beans up (in a thin layer) of the vacuum packs and placing them gently in the water bath.

    Thoughts on this? Not sure how important the cheese cloth and such are in your set up.

    Thanks for this blog! Good stuff.

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    Replies
    1. Hi! Thanks you for visiting the blog. Please make sure to check my youtube video as well, found by punching in Natto Dad.

      1)When pressure steaming, which is putting the soybeans in a strainer and suspending over the boiling water, the beans have to be soaked for at least 20 hours. I have never tried putting pressure steaming dry soybeans but I think it would not plump up and cook in time.

      2)I have not used a sous vide to make natto as I do not have the setup to do so. I am aware of this cooking method. You could use the water bath for heat but the natto needs air to grow being aerobic so vacuum sealing it might suffocate the natto bacteria. If the fermenting container could be suspended in the bath, I think it would work nicely.

      Not covering the top with plastic wrap or cheese cloth will dry out the surface and natto does not grown well when dry. So I suggest covering it while allowing a little bit of air to get in.

      Hope that helps! You can also use my nattodad@gmail.com as I do not think you get reply notifications when commenting on the blog. Let me know how it goes! -Natto Dad

      2)

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