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 koji is made.

So, essentially, koji is steamed grains which have koji starter mold grown on them.

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

What is Koji Rice?


Kori rice is considered to be the beginning of traditional Japanese food culture of "fermentation", and its roots date back to the Nara era.

Koji is a type of mold, called koji starter, grown on steamed rice or wheat. For koji rice, the koji starter in grown on steamed rice

You may think that it's weird to eat mold--well, fungus--but although it's mold, the koji starter mold is fungi that are useful for humans. The fungus that is used for koji starter is Aspergillus oryzae.

Koji rice is steamed rice that has been propagated and fermented with koji starter.

It has a very close and deep relationship with Japanese dishes, and koji rice is used as a raw material for miso, soy sauce and mirin.
It is also used to make a Japanese non-alcoholic traditional drink, amazake (sweet sake).

Why Use Koji?

Why should we try to use koji into your foods?

Will it be any different if you add koji into your dishes?

Check these out!

Mixing Koji with Seasonings Makes It Even More Delicious


koji with seasonings

There is one kind of koji called salt koji (or shio koji in Japanese).

Shio koji is made by mixing rice koji, salt, and water, then ferment it.

Along with shio koji, a very popular seasoning is shoyu koji (soy sauce koji), which is also made by adding rice koji to soy sauce and ferment it.

When you add koji to seasonings, the seasonings become more delicious because koji will bring "umami" taste to it.

"Umami", source of savory flavor, is considered as one of the 5 fundamental tastes along with sweet, sour, salty and bitter.
Glutamic acid and Inosinic acid are what makes the umami flavor.

"Umami" is a flavor that you'll taste when food contains glutamic acid and inosinic. Koji contains a lot of this glutamic acid.

Therefore, you can taste umami strongly in koji, or foods that contain koji in it.

There are also various recipes using rice koji in this section.


Koji Rice is Rich in Enzymes


Koji Rice is Rich in Enzymes

The enzymes contained in the koji rice help the body absorb the nutrition of the ingredients better.

If you eat vegetables and meat along with koji-rice-based foods, you can get better absorption of the nutrients from those vegetables and meats.

It can also help the gastrointestinal function by smoothening digestion and absorption process of the foods you ate.

Dishes that using koji rice as ingredient are also have a great deal of attention from health perspective.


Helps Lactic Acid Bacteria Work Better


The enzyme contained in the koji has the function of producing oligosaccharides.

Oligosaccharides have a role to support the activities of lactic acid bacteria that exist in the intestines.

The activation of good bacteria such as lactic acid bacteria in your body improves the intestinal environment and improves immunity.

Especially amazake which is made from rice koji, is said to work particularly well in the intestines.

How to Use Koji Rice

Recently, the number of people who want to try fermented foods using koji rice at home is increasing.

Especially amazake made from handmade koji rice is said to have high nutritional value because it is fresh and rich in taste, and a lot of koji molds are alive.

You can use koji rice into various foods!
Here are some handmade recipes using koji rice.


Amazake (Sweet Sake)


Amazake made with koji rice is safe for children because it does not contain alcohol components.

In Japan, it's also called "飲む点滴; nomu tenteki" meaning "drinking IV drips" because of its rich nutrition.

We will tell you more about amazake and how to make amazake in the article below!


 

 

amazake sweet sake

How To Make Amazake (Sweet Sake)
For those who make amazake for the first time, amazake made with koji rice alone is recommended.
From rice koji amazake you can enjoy the original flavor, aroma, and sweetness of koji.
Use high quality koji rice and enjoy the deep sweetness!

Read the article of "How To Make Amazake (Sweet Sake)" here.

 

 

Brown rice amazake

What is Brown Rice Amazake
Brown rice amazake is a amazake made from combining brown rice and koji (Aspergillus Oryzae) by fermenting it.
There are two types of amazake, one made from sake cake and one made with koji and rice.
Brown rice amazake is a amazake made from brown rice and koji, therefore sugar and alcohol are not included at all.

Read the article of "What is Brown Rice Amazake" here.



Miso


Making miso by yourself might take time, but it also brings a lot of attachment and love into it.

You can also enjoy miso flavor that is a bit different from commercial products.

We will introduce recipe for making miso paste using koji rice.


 

 

how to make miso

How to Make Miso
We will tell you about the recipe of how to make miso paste.
This recipe is an instruction from miso manufacturer summarized by Kawashimaya.
You can use this as a reference to make your own miso.
Please enjoy making miso to your heart's content. We hope that you can make delicious miso!

Read the article of "How to Make Miso" here.



Shio Koji (Salt Koji)


Salt koji, the one which also sparked the "koji boom".

You can easily make it at home if you have the ingredients!

If you have salt koji, the range of cooking recipes you can make will be much wider.


 

 

salt koji shio koji

How to Make Salt Koji (Shio Koji)
In recent years, shio koji or salt koji has been featured in TV commercials and magazines throughout Japan.
It is added to the menu at homes, restaurants, and chain restaurants.
Because of its easiness of use and its addictive taste, salt koji is said to be a universal seasoning.

Read the article of "How to Make Salt Koji (Shio Koji)" here.

Dried Koji vs Raw Koji

raw koji

Dried koji refers to koji that has been dried by removing the water content of raw koji (fresh koji).

Miso and amazake made with raw koji have better taste and aroma than dried koji, and they can make fermented foods in a shorter period of time.

However, raw koji has a drawback that it has a lot of moisture (because of the water content), so it's easy for bacteria to propagate and it cannot be stored for a long time.

Because we couldn't keep the finished raw koji for a long period of time, thus dried koji was made.

For the dried koji, only the amount you want to use at that time is rehydrated back to raw koji with water, and the rest can be stored again.

If you want to make a small amount of amazake, miso, or koji rice at home, using dried koji rice is recommended.


How to Rehydrate Dried Rice Koji


We will guide you to how to rehydrate dried koji with water.

If you have dried koji and a bowl, you can easily do it, please refer to this article!

How to Rehydrate Dried Rice Koji

How to Rehydrate Dried Rice Koji
This tutorial is made by Kawashima The Japanstore using advices from the manufacturer of the dried koji themselves.
You can refer to this article to rehydrate dried rice koji!
Enjoy making koji in a way that is easy to make according to your home environment and preferences.

Read the article of "How to Rehydrate Dried Rice Koji" here.

Health Benefits of Koji

koji rice for health

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)

koji rice for health

There are some research that shows rice koji can have effects in reducing body weight gain, fat accumulation, and blood glucose level in high-fat diet-induced. (source)

Koji contains glycosylceramide, which has improving effects of skin and intestinal microbial flora. Koji can functions as a prebiotic in gastrointestinal function. Koji might be the connection between Japanese cuisine, intestinal microbial flora, and longevity. (source)



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%.

Where to Buy Koji Rice and
Recommended Koji Rice

where to buy koji rice

Dried koji rice may not be easy to find in store outside Japan.
But you may found dried koji rice in food stores which sell Japanese or Asian food ingredients near you.

Here in Kawashimaya the Japanstore, we sell various kind of koji, as well as dried koji!

Most of the dried koji can be stored for a long time and can be used for making various fermented foods.

Here we will introduce recommended dried koji rice grouped by the purpose of use.



Recommended Dried Rice Koji for Making Amazake (Sweet Sake)


A perfect dried rice koji for making amazake.
Because of high sugar content in this dried koji, even without adding sugar, it will have firm sweetness and richness of flavor.



amazake sweet sake

How To Make Amazake (Sweet Sake)
For those who make amazake for the first time, amazake made with koji rice alone is recommended.
From rice koji amazake you can enjoy the original flavor, aroma, and sweetness of koji.
Use high quality koji rice and enjoy the deep sweetness!

Read the article of "How To Make Amazake (Sweet Sake)" here.



Recommended Dried Koji Rice and Barley Koji for Making Miso


Here are koji rice and barley koji, which are indispensable for making miso.

In homemade miso, you can enjoy the taste of fresh miso that is not available in the commercial miso.




how to make miso

How to Make Miso
We will tell you about the recipe of how to make miso paste.
This recipe is an instruction from miso manufacturer summarized by Kawashimaya.
You can use this as a reference to make your own miso.
Please enjoy making miso to your heart's content. We hope that you can make delicious miso!

Read the article of "How to Make Miso" here.



Recommended Dried Koji Rice for Making Shio Koji (Salt Koji)


A salt-koji-making set that you can easily use at home.

With salt koji, the range of cooking recipes you can make will be much wider!



salt koji shio koji

How to Make Salt Koji (Shio Koji)
In recent years, shio koji or salt koji has been featured in TV commercials and magazines throughout Japan.
It is added to the menu at homes, restaurants, and chain restaurants.
Because of its easiness of use and its addictive taste, salt koji is said to be a universal seasoning.

Read the article of "How to Make Salt Koji (Shio Koji)" here.



Koji Rice Powder: Easier Way to Get the Nutrients of Koji Rice


There are many people who said, "I want to incorporate rice koji, which is good for health and beauty, into my life more easily."

Based on such wishes, we have developed a product through many trials-and-errors, "Koji Rice Powder".




rice koji powder

Koji Rice Powder Recipes
Fermented foods that you want to eat little by little every day to maintain health.
Koji rice powder is rich in nutrients and contains many enzymes that support the intestinal environment, and have great effects on improving immunity, beauty, recovery from fatigue, etc.
Read the article of "Koji Rice Powder Recipes" here.

You Can Also Make Koji Rice At Home!

Nowadays, fermented foods using koji are attracting attention, and the number of people who can make koji at home is also increasing.

Ypu can use koji rice as a base, then make miso and amazake with it.

We will introduce how to enjoy making koji at home!
Which, until now, it was only possible to be done at koji breweries and specialty stores.


 

 

how to make rice koji

How To Make Koji Rice —Without Fail!
This recipe is an instruction from koji rice manufacturer and summarized by Kawashimaya.
You can use this as a reference of how to make koji rice.
Please enjoy making koji rice to your heart's content. We hope that you can make nice koji rice!

Read the article of "How To Make Koji Rice" here.



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


Now, let's start making koji rice!

Koji Rice Q&A

How do I use rice koji?
It's good to put it on meat and fish, rice koji will make your meat and fish more delicious.
Yu can also use rice koji to make amazake and miso, or mix it with salt to make salt koji.
Check this section to know more about how to use rice koji
What are the health benefits of eating koji rice?
There are various health effects of koji rice.
It's good for cancer prevention and healthy skin. It also can improve immunity, support the intestinal environment, and helps you recover from fatigue faster.
Where can I buy koji rice?
You may found dried koji rice in food stores which sell Japanese or Asian food ingredients near you.
Maybe it'll be more convenient to buy it from online store, though.
Here in Kawashimaya the Japanstore, we sell various kind of koji, as well as dried koji. Please check this section.

Recommended Product to Make Koji Rice