Koji: The Starter Mould
Seven pages on the mould that starts everything: what koji is, its three bases, the two everyday koji seasonings, amazake, sake lees, and how to choose a starter.
The full list sits in the frame below - it scrolls inside the frame so the rest of the page stays close.
What Is Koji?
Koji is grain or beans carrying a cultivated mould, Aspergillus oryzae - the starter behind miso, shoyu, amazake and sake.Rice Koji, Barley Koji and Soybean Koji
The three classic koji bases. The grain or bean the mould grows on decides which seasoning the koji is suited to make.Shio Koji (Salt Koji)
A salty, lightly sweet seasoning paste of koji, salt and water - used as a marinade and all-purpose salt substitute with extra depth.Shoyu Koji (Soy Sauce Koji)
Koji matured in soy sauce instead of salt water - a dark, ready-to-use seasoning with the depth of shoyu and the sweetness of koji.Amazake
A sweet, thick drink made in two distinct ways - from koji alone, or from sake lees. The two kinds differ in alcohol and in taste.Sake Kasu (Sake Lees)
The pressed solids left after sake is separated from its mash - sold as flat sheets or paste, and used as a seasoning and pickling bed.Choosing a Koji Starter: General Principles
Dried koji and tane-koji spores are sold internationally. This page gives the general principles only - not home long-fermentation procedures.
Koji is grain or beans carrying a cultivated mould, Aspergillus oryzae - the starter behind miso, shoyu, amazake and sake.Rice Koji, Barley Koji and Soybean Koji
The three classic koji bases. The grain or bean the mould grows on decides which seasoning the koji is suited to make.Shio Koji (Salt Koji)
A salty, lightly sweet seasoning paste of koji, salt and water - used as a marinade and all-purpose salt substitute with extra depth.Shoyu Koji (Soy Sauce Koji)
Koji matured in soy sauce instead of salt water - a dark, ready-to-use seasoning with the depth of shoyu and the sweetness of koji.Amazake
A sweet, thick drink made in two distinct ways - from koji alone, or from sake lees. The two kinds differ in alcohol and in taste.Sake Kasu (Sake Lees)
The pressed solids left after sake is separated from its mash - sold as flat sheets or paste, and used as a seasoning and pickling bed.Choosing a Koji Starter: General Principles
Dried koji and tane-koji spores are sold internationally. This page gives the general principles only - not home long-fermentation procedures.
Sources: Ministry of Agriculture, Forestry and Fisheries (MAFF), 'Traditional Foods in Japan'; JAS soy sauce standards; Umami Information Center; Kikkoman official information; Wikipedia (CC BY-SA 4.0). Checked 6 November 2026.
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