What is Koji | Rice Koji and Amazake Specialty Store Ren MURO Muro [Official Mail Order]

Hello. This is Ren MURO Kagurazaka store.

Today, I would like to talk about "koji", which is indispensable for making koji amazake.

It may be a little difficult, but knowing this will deepen your understanding of amazake.


・About Aspergillus oryzae

Aspergillus aspergillus oryzae is indispensable for making "sa-shi-su-se-so" such as soy sauce and miso, which are the basic seasonings of Japanese cuisine. Japanese food culture cannot be described without koji. For this reason, in 2006 , the Brewing Society of Japan designated koji mold as a "national fungus."

Aspergillus oryzae has three representative types of national fungus, and the fermented food produced by each type is different.

(1) Aspergillus oryzae (scientific name: Aspergillus oryzae ) amazake, sake, miso, soy sauce

② Aspergillus sojae: Aspergillus sojae Soy sauce

③ Asperguillus luchuebsis Shochu, Awamori


・What is koji?

Koji is steamed rice, soybeans, etc., in which koji mold is propagated.

If koji mold is propagated in rice, it will be “rice koji”, and if it is propagated in soybeans, it will be “bean koji”.

The original koji mold that makes this koji is called "tane koji". The place that sells this koji starter to miso, soy sauce, and sake breweries is called a koji starter shop (also known as a moyashi shop).

One of them is the long-established Kyoto koji seed maker "Hishiroku", which is also available at Ren MURO . It is said that the origin of the name “Moyashi-ya” comes from the appearance of the hyphae of koji mold, which looks like a vegetable bean sprout.


・Enzymes contained in Aspergillus oryzae

Koji mold contains more than 100 kinds of enzymes.

There are three main types: amylase, protease, and lipase.

“Amylase” breaks down starch to form glucose. It is thanks to this amylase that koji amylase is sweet without the use of sugar.

"Protease" breaks down proteins to form amino acids, which are the source of umami. The action of this protease is what makes the meat softer and more flavorful when the meat is dipped in shio-koji.

“Lipase” breaks down fats into fatty acids.


Amylase and protease have the effect of helping digestion and absorption, and it is easy to lead to improvement of the intestinal environment.

It also contains all 9 types of B vitamins and essential amino acids, so it can be used not only for cooking, but also delicious and healthy.


Koji, which contains such enzymes, is one of the wonderful traditional Japanese fermented foods.

By all means, I would like to incorporate it into my daily life.


It was a little technical content, but I would appreciate it if you could understand a little bit about koji.

Until the end Thank you for reading.




Noren MURO Kagurazaka

Address: 1-12-6 Kagurazaka , Shinjuku -ku, Tokyo 162-0825

Phone number: 03-5579-2910

Website URL : http://noren-japan.jp/store/murokagurazaka/

EC site URL : https://koujiamasake.jp/

Instagram : https://www.instagram.com/noren_muro/


  • 米麹・甘酒専門店 MURO神楽坂

    MURO(むろ)は、麹を製造する神聖な場所「麹室(こうじむろ)」が名前の由来です。「KOJIを通じて、人々の健康や豊かな食に貢献する」をコンセプトにしたKOJI FOODS(麹を使った食品・調味料)やKOJI DRINK(甘酒)のブランドです。
    店舗には管理栄養士や発酵食品ソムリエなど、甘酒好き、甘酒通のスタッフが体質やお好みを伺って お客様に合うような甘酒の種類や飲み方を提案しております。
    沢山のこだわりの甘酒の中から、ぜひお気に入りの一本、お気に入りの作り手さんに出会って 日々の体と心の健康にお役立ていただけますと幸いです。