Gekkeikan launches a cooking sake born from koji mould research

Gekkeikan, a major sake brewer in Fushimi, Kyoto, launched its “Premium Junmai Cooking Sake” in Japan on 14 September 2026. Its distinguishing feature is that it contains deferriferrichrysin (Dfcy), a natural component derived from koji mould that the company has researched for more than 20 years. Koji mould is a type of mould essential to sake brewing because it converts the starch in rice into sugar. Gekkeikan has turned the results of that research into a product for the kitchen, as a seasoning rather than a drink.

Making use of a component once seen as a nuisance

Dfcy was traditionally treated as something to be removed during brewing, because it gives sake an unwanted colour. Gekkeikan turned that thinking on its head and began investigating the component’s properties in 2003. As a result, the company established that Dfcy has a strong antioxidant effect. Through further research, it developed its own koji mould strain that produces large amounts of Dfcy, and a patent application is currently pending. What makes this story interesting is that something regarded as a “flaw” in the brewing world was found to have new value.

Curbing fat oxidation to reduce odours

Part of the unpleasant smell of meat and fish arises when the fat in the ingredients oxidises. Gekkeikan explains that the antioxidant action of Dfcy suppresses this oxidation and so limits the development of odours. It says the sake suits the preparation of fatty ingredients such as pork belly, minced meat, yellowtail, mackerel and sardines, as well as quick-simmered fish dishes. Other suggested uses include softening the beany smell typical of soy meat and the smell produced when cooking old rice.

A junmai, salt-free design

The sake is made only from domestic rice and rice koji, and is a “junmai”, meaning no brewer’s alcohol is added. Amino acids derived from the rice add umami and richness. Because no salt is added, it is easy to adjust the seasoning, and it can be used from preparation through to finishing. In Japan, the suggested retail price is 600 yen (excluding tax) for a 500 ml carton, and the alcohol content is 13%.

At present, only a launch in Japan has been announced, and there are no announced plans to sell it in Europe. Even so, the product tells us something. Sake koji is no longer just an ingredient for a drink; it has become a subject of food technology research. In European kitchens, too, sake can be used much as wine is, to marinate meat and fish or to finish a stew. For cooking, choosing a salt-free junmai sake rather than a salted “cooking sake” makes it easier to control the flavour. It will be worth watching whether products with new koji-derived functions make their way overseas.

References and sources

• Gekkeikan news release (11 September 2026)