Fermentation aids (hakko josei zai)

Fermentation aids are substances used to support the fermentation process and ensure healthy brewing. In sake brewing, these aids may be added to the brewing water or at various stages of the brewing process. Examples include lactic acid, table salt, potassium dihydrogen phosphate, calcium dihydrogen phosphate, ammonium phosphate, magnesium sulfate, and ammonium sulfate. By promoting fermentation and improving the brewing environment, these components help raise the quality of the finished sake. Fermentation aids play an important role in achieving more stable fermentation by supporting the activity of the yeast and helping to suppress unwanted bacteria.