Filamentous fungi (shijokin)

Filamentous fungi (shijokin) are a type of microorganism made up of elongated cells, generally characterized by structures called hyphae. Because these fungi lack chlorophyll, they cannot photosynthesize and obtain nutrients mainly by living on dead organic matter (saprophytism) or by parasitism. In sake brewing, some filamentous fungi can be useful and may play an important role, particularly in making koji. However, depending on the type of filamentous fungus, they may affect the flavor and quality of the sake, so they need to be managed during the brewing process.