Fuzo (spoilage of moromi)

Fuzo refers to the spoilage of sake moromi (fermentation mash) caused by unwanted microorganisms. These spoilage organisms include, for example, lactic acid bacteria and wild yeasts. When they invade the moromi, fermentation does not proceed normally, and the mash turns sour or gives off an unpleasant odor. Once fuzo occurs, the quality of the moromi drops significantly and it becomes unfit to drink, so it is generally, regrettably, discarded. In sake brewing, hygiene management is extremely important, and brewing in a clean environment is required to prevent fuzo.