These are the seeds of the mould that is used in the conversion of starch to sugar and is responsible for the complex and interesting flavors created in the brewing process. A 10 gram packet will produce approximately 6 kilos of Koji Rice (rice that has been enriched with enzymes from the growth of Koji). This will produce approx 22 litres of Sake.
The koji seeds are dry and extremely stable and are stored in an air lock bag. They have an indefinite shelf life being dried conidia, they need no refrigeration and the packet can be opened and closed frequently without harm done to the contents.