Hiochi (spoilage caused by hiochi bacteria)

Hiochi is a phenomenon that occurs during sake production when hiochi bacteria (hiochikin) multiply. It can make the sake turn cloudy white, increase its acidity, and produce a characteristic off-odor known as hiochi aroma. This odor is attributed mainly to diacetyl and volatile acids, and is described as reminiscent of the morning sickness of early pregnancy. Once hiochi occurs, the flavor of the sake deteriorates and its quality declines, so hygiene management during brewing is important.