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 koji 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%.



The Benefits of Handmade Koji

    • ■ 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 ingredients 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 and barley 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


Now let's make barley koji!



How to Make Barley Koji




Hello, welcome to Kawashima the Japanstore.

In this article I will explain a way to make barley koji (fermentation starter, in this case Aspergillus oryzae, breeded on wheat/barley).

This recipe is an instruction from koji manufacturer summarized by Kawashimaya.

You can use this as a reference of how to make barley koji .

Please enjoy making barley koji to your heart's content.

We hope that you can make nice barley koji!


Work process of making barley koji
Wash the barley, then soak it in water → Drain water from the barley → Steam the barley → Sprinkle the koji seed → Keep the barley warm → 18-20 hours → First maintenance of koji → 5-6 hours → Second maintenance of koji → 7-8hours → Completion of koji


Tools and Ingredients (For 250g of finished amount)


Pearl Barley Koji seed (koji starter)
Steaming cloth Steam cooker or steamer
Koji fermenter (You can also use Yogurtia or cooler box)





    • ・ Steam cooker or steamer

    • ・Koji fermenter device or warming device (fermentation device/box for koji; you can also use Yogurtia or cooler box)
      → Koji Fermeter's Page


Click here to see our Recommended Product for Barley Koji


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 Amount of Barley Koji That Can be Made and the Amount of Barley and Koji Starter Used

Portion of barley

Portion of koji starter

Amount of finished barley koji (estimated)

The Amount of the Rice and the Koji Starter Being Used, and the Finished Koji Rice,
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 barley koji and koji starter seed.
For the koji starter, it is easier to make barley koji 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).



The Steps of Making Barley Koji


1. Wash the barley, then soak it in water
2. Drain water from the barley
3. Steam the barley
4. Sprinkle the koji seed (koji starter) on steamed barley (seeding)
5. Keep the barley warm (18-20 hours)
6. Untangle the in-fermenting-process barley (First maintenance of koji)
7. Second maintenance of koji
8. Completion of koji


Click here to see our Recommended Product for Barley Koji



Step 1, Wash the Barley, Then Soak It In Water (for about 1 hour)


Wash barley, soak barley

Wash the barley two or three times until the white dirt disappears.

Then add clean water until the barley is all soaked and immerse it.

The appropriate time to soak the barley in 20℃ water is about 1 hour.

Since barley has fast speed of water suction, don't soak it in water for a long time.



Step 2, Drain Water from the Barley (about 30 minutes)


Drain water

Take the barley with strainer, and drain it for about 30 minutes.

As water will remain in the bottom of deep strainer,
please use shallow strainer so the barley can spread and drained from water nicely.
If there's water left, the finished result will not be good barley koji.

Also, if in the middle of draining process you stir the barley, or wipe the strainer,
the surface of barley may be scraped into powder, causing stickiness.
Please put the barley on strainer and leave it as it is when draining the water.



Step 3, Steam the Barley


Steam the barley

Wrap the barley with steaming cloth, then steam it with a steamer
It's important to steam the barley with strong steam.
The steaming process here affects the finished result of koji greatly.


If you steam it with houseware steamer, the period of steaming is approximately 40-50 minutes.
The period of steaming will vary depends on the fire strength used.
Please steam the barley slowly and set the fire not too strong so the heat can nicely pass through the core of the barley.

When the barley grain became translucent, elastic, there was no core when you pinch it,
and its texture is just springy like a mochi, then the steaming condition is good.

Steaming condition

When steaming with weak steam for a long time, please be careful as it will become koji with high water content.

While waiting for the steaming process to be done, please prepare the koji fermenter device and warm it until 35℃


Step 4, Sprinkle the koji seed (koji starter) on steamed barley (seeding)


Sprinkle koji starter

When the barley is steamed up, put and spread it on a clean tray or a clean dish cloth. ※Please be careful not to burn yourself.

Cool the temperature of the barley by spreading it with rice paddle.
Sprinkle the koji starter when the barley temperature reaches 35-40℃.

This steep is called "seeding".
When you sprinke the koji starter (seeding), it's convenient to use tea strainer.
If you spread the koji starter when the barley is still too hot, it will kill the microoganism (Aspergillus) in koji starter.

Also, if the koji starter is sprinkled after the barley has completely cooled down, fermentation process won't go well.
After estimating the timing when the temperature of barley is 35-40℃, quickly mix the koji starter on barley.
In order to spread the koji starter on the barley thoroughly, do the sprinkling of koji starter with tea strainer then mix the whole barley, repeat this for several times for the good result of this seeding step.


Seeding

The amount of koji starter used is usually 1g of koji starter (koji seed) for 500g of barley.
But 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 3 to 4 times of that amount.

After you finished the seeding, quickly gather the barley together and wrap it with a clean cloth.
When wrapping it with cloth, wrap it roundedly as small as possible by applying force.


Wrap with cloth



Step 5, Keep the Barley Warm (18-20 hours)


Keep warm

Put the wrapped barley on the koji box, then put it in the koji fermenter device/box.

In this step, the optimum temperature of the surface of the barley is around 30-35℃.

If you don't have any fermenter device, you can use kotatsu or a cooler box.



Step 6, Untangle the In-fermenting-process Barley (First Maintenance of Koji)


First Maintenance of Koji

When it's about 18-20 hours from you start warming the barley koji,
due the activity or sprouting/budding of koji starter, the temperature of the barley will rise
and there will be a sweet aroma of koji from the fermentation device/box.

When the temperature of the barley rises to about 38 to 40℃,
took the barley out from the fermenter device/cooler box, untangle the clumps of the barley, and lower the temperature of barley.
After you finished untangling the barley one by one, wrap it in cloth again.

By doing this maintenance, the clumps of barley are untangled, making the temperature is at the same rate on all the barley,
and air spreads throughout koji, thus accelerate the breeding of koji starter.

If the fermentation progress is going well, due to the growth of koji starter,
there will be something like white dots come out on the surface of the barley.
Do the maintenance (untangling) quickly so that the temperature of barley doesn't go down.
Put the barley back in the fermentation device, and keep it warm for 5-6 more hours.


Step 7, Second Maintenance of Koji


Second Maintenance of Koji

When 5-6 hours has passed from the first maintenance of koji,
the koji starter will further breed and the temperature of the barley koji will rise again to 36-40℃.

At this moment, once more, quickly untangle the clumps of barley and stir the whole of barley koji.
This time also, keep in mind to do the maintenance quickly so that the temperature of barley does not go down under 30℃.

After the second maintenance of koji, keep it warm again for 19-21 more hours.
After that, it will be good to keep going to do maintenance of barley koji at any time when the temperature rises above 38℃.


Step 8, The Completion of Barley Koji


Completion of Barley Koji

After 19-21 hours from the second maintenance (42-48 hours from sprinkling the koji starter on steamed barley {seeding}),
If the scent like chestnut is coming out, then a good quality of koji is completed.
Since the speed of growth of the koji starter (Aspergillus) varies depending on temperature and humidity, the time it takes until the koji is completed is also changed.

Please check the breeding/growth condition of koji.
If there is no problem in the breeding condition of koji starter on barley koji, the it's completed.

The indication of the completion of koji is that if the hyphae of koji starter stretches out,
the barley sticks to each other and becomes a plate shape, and easy to disentangle by hand.


 

How to Store the Barley Koji (Presevation Method)

After the barley koji is completed, it's recommended to use the koji as soon as possible.
When storing in a refrigerator, put it in hygroscopic (material that tends to absorb moisture from the air) paper bag.
In the refrigerator, you can save the barley koji for about 1 week.

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.
You can save the barley koji for about 1-3 months in freezer.

Miso and Koji

When used for making miso, mix the barley koji with salt.



How to Make Barley Koji Q&A



I feel that there is much water content (moisture) in the steamed barley. How should I decide the proper condition of steaming?
When crushing the steamed barley grain with your finger, it's ideal if the barley is elastic and not sticky.

If it's discolored to yellowish-brown/amber color, plump and elastic,
and the surface is not sticky, then it's in good contidion.
If there is steamed barley(s) which has a large white spot at the center, it is low in water absorption.
I steamed the barley with weak steam for a long time, and it became gooey (a lot of moisture).
Please steam with the strong steam so the heat can gush out from the top immediately.
If the steam is weak, moisture will increase rapidly because the steam cannot go out and condenses in barley.
If it takes a few minutes for the steam to come out from the top, obviously the steam is weak.
Even after maintenance, the temperature of barley koji immediately rise again to over 40℃.
If the temperature immediately rise again after you do the maintenance,
it is a proof that the breeding speed of koji starter is prosperous.
Since barley koji has a large calorific value during propagation, its temperature is easier to rise that koji rice.
Temperature should be checked regularly, and when the temperature exceeds 40℃, please do the maintenace immediately,
because it's necessary to lower the temperature of barley and evaporate the water at the same time.
The color of the finished barley koji is brownish, is that okay?
When the temperature of barley koji is over 40℃, brown substance (melanoidin) may formed.
As the temperature in the fermenter rises high, polysaccharides (starch) are decomposed
to monosaccharides (such as glucose) by the enzyme produced by koji, and
the protein is broken down into amino acids.
When this monosaccharide reacts with the amino acid, a brown substance (melanoidin) is produced
therefore, the color of barley koji will become brownish.

It becomes brownish by the function of koji starter's own enzyme, so it's not contaminated by other microorganisms,
and can be used for making miso without problem.
However, since in miso-making the miso is also colored by other pigment, it will be finished as red-brown miso.
By not letting the temperature of koji to 40℃ or higher, discoloration can be prevented.
The finshed barley koji is sticky.
It is due to lack of maintenance. There is no problem to use the barley koji for miso preparation.

It is important to do the maintenance of koji in the proper timing when the temperature rises.

However, there is no contamination of microorganisms and there is enough enzyme power,
so it can be used without any problem in miso-preparing.
Because the amount of moisture in koji is high, miso tends to become loose, so after miso preparation,
please took out the liquid that ooze out from miso and be careful so the miso don' become too loose.


Recommended Products


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Mini Size Koji Fermenter Kit for Homemaking【Ideal for Making Homemade Tofu and Yeast】
It can be assembled without any tools, in 1 minute. Because it's a mini size, it won't took many space at your home! You can ferment koji rice and bread dough properly by keeping the constant temperature and humidity. With this PF100-48H fermenter device, you can keep the koji rice warm for 48 hours for its fermentation process.


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Pearl Barley (Urabe Farm · Organic Farming Method · Pure Breed Cultivation) 300g
It is 100% domestic organic pearl barley made carefully using organic barley from Urabe Farm, and strictly produced and managed at domestic organic certified factory. Speaking of barley, the familiar one is rolled barley, but if you want to make boiled-barley-and-rice with brown rice, we recommend the pearl barley with good texture.


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Koji Starter (Powdered, in Sachet) 20g - The Best Koji Starter for Making Miso
Established since 300 years ago, this is the koji starter (koji seed) in the powder form, sachet package made by the long-established store "Hishiroku." This is the best koji starter for making miso. The features of this koji starter are well-balanced in enzymatic power and good aroma of traditional koji. You can use this koji starter to make delicious miso.


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Koji Starter (Powdered Kairyou Chouhaku-kin Fungal Seed in Sachet) 20g - The Best Koji for Amazake (Sweet Sake)
Established since 300 years ago, this is the Kairyou Chouhaku-kin variety of fungal seed koji starter in the powder form, sachet package made by the long-established store "Hishiroku." This is the best koji starter for making Amazake. The features of this koji starter are well-balanced in enzymatic power and good aroma of traditional koji. It's best for making amazake (sweet sake), white miso, and other white-colored foods and drinks.


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