What is Koji Starter for Soybean Koji --Special Product From "Hishiroku" Shop, Kyoto This is a koji starter seed made by the 300 years long-established store "Hishiroku." This koji starter...

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What is Koji Starter for Soybean Koji --Special Product From "Hishiroku" Shop, Kyoto

This is a koji starter seed made by the 300 years long-established store "Hishiroku."

This koji starter is koji starter for soybean koji and very suitable for making kinzanji miso.

Kinzanji miso is a mixture of kinjanzi koji (mixed rice koji, barley) koji, and soybean koji) and chopped vegetables, such as eggplants, cucumbers, shiso, carrots, ginger roots, etc

Use this high quality koji starter for making soybean koji, and you can make your own kinzanji koji by mixing it with koji rice and barley koji.

With your delicious kinzanji koji, you can make delicious kinzanji miso!


This product contains 20g of koji starter (Aspergillus) that can be stored for a long time, in conveniently sachet package so you can open it just as much as you need.

This is a very suitable koji starter/koji seed for those who want to make koji at home.

100g of this koji starter can be used for 200kg of soybeans in koji-making (the weight of soybeans before adding water is 200 kg).


We are pleased to inform you that Hishiroku Koji Starter Spores for Soybean Koji (for making Kinzanji Miso) 100g is now available on Amazon USA. Click the link to see the product!


What is Koji Starter/Koji Seed?

Koji starter or koji seed is the Aspergillus spore that becomes the source of koji.

Fermented foods such as miso and amazake (sweet sake) are made from raw koji.

And if there is no koji starter, you cannot make koji.
In the brewing industry, we call the koji starter as "sprouts."
The appearance of the koji starter's bud popped out and its whitish hyphae grows resembles the bean sprouts and budding trees figure, so it's called like that.


Comparative Chart of Koji Starter

Choukaku-kin Koji Starter Kairyou Choukaku-kin Koji Starter Koji Starter for Miso Kinzanji Koji Starter Koji Starter for Shouyu
Koji Starter Koji Starter Koji Starter Koji Starter Koji Starter
Features The finished result is white koji. Basic koji starter that suitable for any kojis. Ideal for amazake (sweet sake). The finished result is the most white-colored that other koji starter. Recommended for white miso. Ideal for rice and barley/wheat miso. The finised result will have a balanced taste. Ideal for bean koji. Increase the flavor of bean miso (mame miso). Ideal for shouyu (Japanese soy sauce). It will have delicious result.
Colors Koji Starter Koji Starter Koji Starter Koji Starter Koji Starter
Amazake (Sweet Sake) Very
but not recommended
but not recommended
but not recommended
Shio Koji (Salt Koji) Very
but not recommended
but not recommended
but not recommended
White Miso Very
but not recommended
Suitable Usable,
but not recommended
Rice and barley/wheat miso Suitable Suitable Very
Suitable Usable,
but not recommended
Bean miso Suitable Suitable Suitable Very
but not recommended
Shouyu (Japanese soy sauce) Suitable Usable,
but not recommended
Suitable Suitable Very

More Fermented Foods Recipe from Kawashima The Japanstore

recipe link
Fermentation Food Recipes
Click Here

What is Koji?

Give water to raw grains (rice, barley, beans, etc.), sprinkle seeds on steamed grains, and culture the seeds under temperature conditions suitable for the growth of Aspergillus oryzae.
That is how this koji starter is made.

Koji has so many kinds of enzymes that it is said to be a treasure house of enzymes, and it decomposes grains with its power.
Also, koji itself is also a nutritious food filled with sugar, amino acids, vitamins, minerals, etc. All these nutritions are made by the koji starter (Aspergillus oryzae).
Using koji, you can make traditional fermented foods such as sake, authentic shochu, mirin, miso, soy sauce, vinegar, amazake (sweet sake), etc.

miso amazake shoyu

Health Benefits of Koji

When the intestinal environment (intestinal flora) gets better, the condition of your skin will be better and immunity will be improved.
It is fermented food that arrange this intestinal environment.
And, fermented foods are always made by microorganisms that induce fermentation.

The familiar ones are such as Aspergillus oryzae, Bacillus natto, Lactobacillus, and other bacteria/fungus.
Among them, the one that creates miso, shouyu (Japanese soy sauce) and sake is koji starter (Aspergillus oryzae).
This koji starter (Aspergillus oryzae) matches well with Japan's climate, and it was found in the Muromachi Period (1336–1573)

Major Nutrients of Koji

    • Vitamin B1 : Helps produce energy | Fatigue recovery | Suppress irritation/stress feeling | Amnesia prevention | Helps breaking down carbohydrates

    • Vitamin B2 : Helps the metabolism of skin | Helps breaking don lipids | Accelerate growth speed | Sebum control | Prevent oral ulcer/stomatitis

    • Vitamin B6 : Reduce premenstrual syndrome (PMS) | Improve immunity | Prevent arteriosclerosis | Helps breaking down proteins and lipids | Prevent oral ulcer/stomatitis | Suppress the excitation of nerve cells

    • Vitamin H (Biotin) : Suppressing the cause of atopic dermatitis | Prevent diabetes | Alleviate epilation and gray hairs

    • Pantothenic acid : Stress resistant | Helps breaking down lipids | Detoxification from chemical compound | Increase good cholesterol | Maintaining the health of skin | Increase immunity

    • Essential amino acids : Among the 20 types of amino acids making up proteins, nine kinds of them can not be synthesized in the body. If there are any lacks of them, muscle, blood, bone cannot be made.
      These nutrients can be consumed in supplements, but when ingested from koji based food, the absorption rate in body is over 90%.

How to Make Soybean Koji

Work process of making soybean koji

Wash the soybeans → Soak the soybeans in water → Sprinkle the koji starter on soybenas → Keep warm → After 18-22 hours → Stir it ① → After 5-22 hours → Stir it ② → After 7-8 hours → Complete

Tools and Ingredients of Making Soybean Koji

Required Tools and Ingredients

Soybeans Koji seed(koji starter) Steaming cloth Koji fermenter (fermentation device)

・ Soybeans (proper amount as you like)
※ Toyomasari soybean is recommended.
→ Toyomasari soybean's page

・ Koji seed (koji starter) for beans
→ Koji seed (koji starter) for soybean's page

・ Steaming cloth 2 sheets
→ Steaming cloth's page

・ Koji fermenter or warming device (fermentation device/box for koji; you can also use Yogurtia or cooler box)

More Convenient If You Have

Thermometer Rice paddle Strainer, tea strainer Koji box (box for koji)

・ Thermometer
・ Rice paddle
・ Strainer, tea strainer
・ Koji box (box for koji)

In order to avoid the breeding of germs, wash the tools clean and properly.
You can disinfect the tools by boiling them.

The Steps of Making Soybean Koji

There are 7 steps for making soybean koji.

1. Wash the soybeans, then soak it in water
2. Boil the soybeans.
3. Sprinkle the koji seed (koji starter) on boiled soybeans (seeding)
4. Keep the soybeans warm
5. Stir the in-fermenting-process soybeans (First maintenance of koji)・・・・(After 18-22 hours)
6. Second maintenance of koji ・・・・(After 22-42 hours)
7. The completion of soybean koji

With these 7 steps, you can make high quality soybean koji.
Let's start making koji!

Step 1, Wash the Soybeans, then Soak Them in Water


Wash the soybeans properly.
After that, discard the dirty water. Then add clean water in the bowl until the soybeans are completely immersed in water.
Wrap it with plastic wrap, and soak the soybeans for about 24 hours.
※When the temperature is high such as in summer, put it in the refrigerator.

Step 2, Boil the Soybeans


Pour the soybeans along with the water used to soak them into a boiling pan, then boil the soybeans.
First, boil the soybeans with high heat until the hot steam rises, then turn to low heat and steam them for 2-3 hours.
If the soybeans became soft enough that when you pinch it with your thumb and index finger it can be easily crushed, discard the hot water. And so the surface of the soybeans can be dried, move the pot and let the hot steam flow away.

Step 3, Sprinkle the Koji Seed (Koji Starter) on Boiled Soybeans (Seeding)


When the soybeans are bolied up, put and spread it on a clean tray or a clean dish cloth.
Please be careful not to burn yourself.
Use a fan to cool the temperature of soybeans.
When the temperature of the soybean have cooled down to 36 degrees, sprinkle the prepared koji tarter seed and mix it thoroughly (this step is called "seeding").
The amount of koji starter is usually about 2g of koji starter on 1kg of soybeans.
For people who try to make barley koji for the first time, it's easier to succeed the breeding of the koji starter if you use 2 times of that amount.
※During this step, please prepare the koji fermenter/warming device and warm it until 30℃.

Step 4, Keep the Soybeans Warm


After the seeding step, move the soybeans to a koji box and spread them flat and thin (about 2-3 dm of thinkness).
So that the soybeans isn't dried off, cover the flattened soybeans' surface with a firmly squeezed clean cloth (disinfect the cloth first with boiling water).
Put it in 28-30℃ pre-warmed fermenter device.
If you keep a humidity by putting a tray of water in the fermenter, there is no need to cover with cloth.

Since soybean koji is more vulnerable to various bacteria than rice koji and barley koji, keep the soybean temperature below 30℃.

For making this koji, the optimal temperature for breeding the koji starter (Aspergillus oryzae) is around 28-30 degrees. Please keep the rice warm at this temperature.
Please be careful for not to drop the temperature.

Step 5, Stir the In-fermenting-process Soybeans (First Maintenance of Koji)・・・・(After 18-22 hours)


By this time, the temperature of soybeans will rise.
Stir (mix) the soybean, lower the temperature and make the thickness of soybean same on all the surfaces.
Stir the soybeans quickly so that the temperature of soybeans doesn't extremely go down.
Also, when stirring soybeans, wash hands and utensils thoroughly.

Step 6, Second Maintenance of Koji ・・・・(After 22-42 hours)


When 5-6 hours passed after the first maintenance of koji, the koji seed will breed further and the soybean temperature will rise again.
Please take out the koji box from the fermenter device and lower the soybean temperature to 28-30℃.
When the temperature of soybeans rises too much, please lower the temperature by stirring the soybeans.
If the temperature rises up too much, contamination by natto bacteria etc. will occur, causing the failure of the koji's completion, so please be careful.
To not raise the temperature of the soybean too much is the important point in the making of soybean koji.

Step 7, The Completion of Soybean Koji


If the surface of the soybeans is covered with green spores and the soybeans became loose, then the soybean koji is ready. Please check the breeding/growth condition of koji.
If there is no problem in the breeding condition of koji starter on soybean koji, the it's completed.
You can use this finished soybean koji to make miso, etc. in your home!

How to Store Soybean Koji

After the soybeans koji is completed, it's recommended to use the koji as soon as possible.
Even if it is kept in the place where the temperature is low and the wind circulation are good, if the mass of the koji rice is thick, the fermentation will not stop and the quality of the koji may deteriorate.
If you plan to save the koji rice for 1-2 days after it's finished, please untangle the clumps in koji rice by massaging it, then spread it as thin as possible and keep it in a cool place.


Store in the refrigerator: about 2-3 weeks

When storing in a refrigerator, put it in hygroscopic (material that tends to absorb moisture from the air) paper bag.
In the refrigerator, it's possible to save the koji rice for about 2-3 weeks.


Store in the freezer: about 1-3 months

If you plan to use it later for a long time, put it in a zip lock (a plastic bag with zipper/fasterner), etc. and keep it in the freezer.
It's possible to save the koji rice for about 1-3 months in freezer.

What A Good Soybean Koji Is


From a good soybean koji, a good aroma like roasted beans will come slightly. If there is an unpleasant smell like a sour smell or a nasty smell, it's most likely that germs have entered and rotted.

Also, spores are grown strongly on good soybean koji. Its texture will be crumbly dan not sticky.
If you want to check it more detail, cut the bean grain with a knife and look at the cross section.
A good soybean koji has a thin white layer between soybeans and spores.

Frequently Asked Questions (FAQ)

How long is the life of koji starter (koji seed)? How long can I keep it?
・ If the package is unopened and stored in a vegetable compartment of a refrigerator etc., the standard for storage period is about 6 months.
・ After the package is opened, please seal it with zip lock etc. and save it in a vegetable room of a refrigerator. With this, you can save the koji starter for about 6 months.
How can I store the finished koji rice?
・ If you want to store it for 1-2 days, please put it in cold dark place with temperature lower than 15ºC.
・ If you want to store the koji rice for 2-3 days, please put it in the refrigerator.
・ If you want to store it for more than 3 weeks, please put it in the freezer. In there, the koji starter can be saved until 3 months.
Can I drink koji starter as it is?
Because it's no a drink, please do not drink it.
For the supplement, we recommed you the KAWASHIMAYA "Lactic Acid Bacteria Powder" - Probiotic Supplement Taken from Japanese Fermented Foods (100 g)
How much shoud I use the koji starter when making koji rice?
The amount of koji starter is about 1.3g-10g for 1kg of rice (rice for raw material) (about 0.2g-2g per 150g of rice)
If you are not used to koji rice making (of first time try) it's better to use the koji starter more.
Even if you use much of it, there will be no problem.

・About the finised amount:
If you steam the rice, the steamed rice will be 1.8-2 times heavier than original/raw weight.
Then, after the koji rice is completed the weight will be 0.9 times of the weight after steamed. Thus, the finished amount of rice koji will be 1.62 (1.8x0.9)~1.8 (2x0.9) times from the weight of original/raw rice.
For example, if the raw rice is 1kg, the finised amount of koji rice is 1.62-1.8 kg.
(This is an estimated amount. The amount of finished koji rice depends on the soaking condition, steaming condition, and the condition of fermentation process.)
The color of finished rice koji is reddish brown and smells strange, can I use it?
There is a high possibility that other bacteria are mixed and proliferating in the process of making it. Please do not use it.
After you sterilized all the equipments, please try increasing the amount of koji starter when making koji rice next time (about 3-4 times more) so it's easier to ferment.
Also, please be careful about temperature control during fermentation process.

Customer's Testimonies

This is the first time I tried to make soybean koji for making soybean miso.
I was a little worried because I couldn't adjust the temperature well, but the result came out just like soybean koji.
I think I can try it more smoothly next time. So, I will repurchase.

Ms. S (30s)

I bought it this year because I wanted to make koji for making homemade soybean miso.
I was impressed that the beans were able to ferment well with the koji starter (aspergillus). I'm even more attached to making miso from scratch.
I'm looking forward to the finished miso.

Ms. Y (40s)

I always use the white-type of koji starter from the Hishiroku store to make koji. I have made koji more than 30 times, but I have never failed.
This koji starter product is useful because you can make various fermented foods using homemade koji.

Mr. H (30s)

It takes a little time to make homemade koji, but I like it because it is much cheaper and produces better quality koji than the commercially available koji.

Ms. Ito (30s)

The Benefits of Handmade Koji Rice

You know exactly what ingredients are being used.

Formerly, in the Japanese family, miso, shouyu, amazake etc. were homemaded with koji. However, the eating habits change with the time, and miso, shouyu, amazake changed from "things to make" to "things to buy." Under such circumstances, there are many people who are uneasy because they don't know what type of rice is used, in foods such as miso and shio koji (salt koji) available at supermarkets etc. If it's handmade, you can make it with pesticide-free rice prepared by yourself so it's safe.

Handmade is fun!

When Kawashimaya's staffs tried to make handmade koji rice, they're impressed that their hands became so smooth. It's a famous story that because they engage in sake-making, the hands of chief brewer at sake (Japanese liquor) brewery is beautiful. In koji rice's nutrients, there are a lot of components that make the skin beautiful. Then, if you make koji rice by yourself, you will take care of it like your own child. Thus, the miso and amazake you made will become more delicious.

It's more economical.

When making miso, you will need koji in kilograms. If you buy it, it will be really pricey. For that, if you make your own koji using koji starter (Apergillus oryzae), it will be much more economical because you can even make koji rice from 15kg of rice.

Handmade Homemade Koji

Koji and Rice
The Steamed Rice, is What Determines the Quality of Koji Rice
If the rice used in koji rice making is cooked with rice cooker or the like, the amount of water (60% or more) becomes too much, and it won't be finished as a good koji rice.
In order to make the rice with moderate water content (about 38%), it's necessary to "steam" the rice with proper steam.
The professionals in koji-making are making steamed rice with bamboo steamer (seiro).
Furthermore, by using steaming cloth made of tetoron, the time loss (temperature drop) caused by the rice sticking on the cloth can be eliminated, so you can do the seeding step (sprinkling the koji starter on steamed rice) smoothly.

The Amount of The Koji Rice That Can be Made and the Amount of Rice and Koji Starter Used

Portion of rice

Portion of koji starter

Amount of finished koji (estimated)

The Amount of The Koji Rice That Can be Made and the Amount of Rice and Koji Starter Used

Note: 合 is a Japanese unit of measurement, usually used to measure rice, sake, etc. (1合 equal to approx. 150 grams, 0,18 liters, or 0,33 metres square)

This is just a reference to the amount of koji rice and koji starter seed.
For the koji starter, it is easier to make koji rice if you use koji starter in bigger amount. Even if you use a lot of koji starter, there will be no problem.

The Amount of Miso That Can Be Made and the Amount of Ingredients Used

Finished MisoFinished-Miso 2.5 kg 5 kg 7.5 kg 10 kg 12.5 kg 15 kg 17.5 kg 20 kg 22.5 kg 25 kg
Rice KojiRice koji 1 kg 2 kg 3 kg 4 kg 5 kg 6 kg 7 kg 8 kg 9 kg 10 kg
SoybeansSoybeans 500 gr 1 kg 1.5 kg 2 kg 2.5 kg 3 kg 3.5 kg 4 kg 4.5 kg 5 kg
SaltSalt 300 gr 600 gr 900 gr 1.2 kg 1.5 kg 1.8 kg 2.1 kg 2.4 kg 2.7 kg 3 kg
Finished MisoFinished-Miso 2.5 kg 5 kg 7.5 kg 10 kg 12.5 kg
Rice KojiRice koji 1 kg 2 kg 3 kg 4 kg 5 kg
SoybeansSoybeans 500 gr 1 kg 1.5 kg 2 kg 2.5 kg
SaltSalt 300 gr 600 gr 900 gr 1.2 kg 1.5 kg

15 kg 17.5 kg 20 kg 22.5 kg 25 kg
6 kg 7 kg 8 kg 9 kg 10 kg
3 kg 3.5 kg 4 kg 4.5 kg 5 kg
1.8 kg 2.1 kg 2.4 kg 2.7 kg 3 kg
This is the portion for miso with salt concentration 12.5% (sweet flavor).

For the details of how to make koji rice, please go to this page >>How to Make Koji Rice
■Recipes that use koji rice >> >>How to Make Shio Koji >>How to Make Amazake (Sweet Sake)

Koji-making Professionals' Favorite Tools!
Koji-making's Best Friends

Tetoron Cloth

Strong against high temperature, excellent in steaming.
Rice won't stick to the cloth, a very handy steaming cloth.
It's also useful for moisture control during the warming of koji.

Tetoron Cloth
Seiro Bamboo Steamer

Seiro (Bamboo Steamer)

Steamed rice is the key to make koji.

Using bamboo steamer/seiro, steam the rice with high heat for about 40 minutes.
It's also a useful tool for daily dishes.

Tips for Making Steamed Rice from the Professionals

Bamboo steamer is recommended to steam the rice!
Also, tetoron steaming cloth is highly recommended!
Don't forget to steam the rice with high heat.

When steam/vapor comes out from the surface of rice and the surfaces become transparent, cover the steamer basket.

Steam it for about 40 minutes (recommended) after you put on the lid.
When steaming in bamboo steamer that has two or more rows, change the order of rows in midway of steaming process.


Message from Hishiroku Corp., the Maker of Koji Seed Starter - Special Product from Hishiroku Shop, Kyoto

In the main region of "The Land of Royal Castle" of Kyoto, standing there for over 300 years is the reputable "Hishiroku" Shop. In its long history, we devotedly making steady progress of koji starter (koji seed).

We believe that small activities hidden in koji starter's Aspergillus will eventually produce big things and will become life force for tomorrow, so we are making research and efforts to deliver the pure, stable, and high quality products of koji starter.

We are looking forward to your further patronage in using Hishiroku's koji starter for making koji.

Hiroshiku Koji starter

Hishiroku Corp.

Product's Details

Name Koji Starter for Soybean Miso (Powdered, in Sachet) - Best for Making Kinzanji Miso
Netto 100 grams
Expired Date About half a year
Storage Method Please put it in cold dark place with temperature lower than 15ºC.
Koji starter Kinzanji Miso 100g

Important Points

  • Be sure to clean up tools, cloths, hands etc. properly and be careful so that germs etc. don't get in.
  • Please use as soon as possible after you open it.
  • This product is for rice koji and barley koji. Please do not use it for other purposes.
  • We will deliver it in a thick envelope.【For Japan region, this product will be shipped by Kuroneko Mail. For outside Japan, this product will be shipped by EMS.】
  • The product will be mailed to your home. (If it's stolen or damage of goods occurs after being mailed, refund or exchange can not be done, please notice beforehand.)
  • Delivery days will be 1-2 days in Japan region and 1-2 weeks outside Japan. Depending on the area, it may take longer.
  • We make it so that the product will arrive as soon as possible, but we can not deliver it on exact date or time of arrival.
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