Kouji: The National Fungus of Japan

If you have ever traveled to East Asia, visited a Chinatown, or studied Chinese and/or Japanese, you likely have come across the character 酒.  In Chinese, it is pronounced jiǔ, and in Japanese, generally it is さけ (sake) or しゅ (shu).  The character originally referred to wine, but now encompasses all liquor.  Harking back to when pubs doubled as places to spend the night, in China, 酒店 –  jiǔ​diàn –  means “hotel,” although it literally means “liquor store.”

Referring to the above photo, 甘酒, or amazake, can be translated as sweet liquor, or sweet sake.  Yet, written right below that word in the picture is the phrase ノンアルコール, meaning non-alcoholic.  How can that be?

A bit of backstory: the full name of the drink is 米麹甘酒 (こめこうじあまざけ) komekouji amazake, or malted rice sweet sake.  The key element of the name is the character 麹, aka 糀, which is koji/kouji, a fungus primarily used to ferment soybeans, in addition to aiding in the creation of rice vinegar and alcoholic beverages.

Kouji was first discovered in China more than 2, 300 years ago., and introduced to Japan around 300 A.D.  To create kouji, spores of a fermentation culture, called Aspergillus oryzae, are injected into rice that has been steamed and then cooled. After a couple of days of being stored in a warm place, as A. oryzae begins to break down the proteins and carbohydrates of the rice, the fungus begins to form.  Finally, the kouji is separated from the decomposition, ready for their task in preparing our favorite soy sauces, mirin, and liquor, among other products.

Indeed, it is the fermentation process that explains why the amazake drink isn’t mislabeled, and why kouji has become Japan’s 国菌 (こっきん) kokkin, or national fungus.


Among these two titans of international cuisine, it’s always fascinating to learn about the humble ingredients quietly playing their parts behind the scenes.