Nikkoshu (sunlight taint)

Nikkoshu (日光臭, "sunlight taint") refers to an off-aroma that develops when sake is exposed to sunlight or ultraviolet light for a long time. It occurs when components of the sake are degraded by light, producing a burnt-like smell or other unpleasant odors. In particular, when bottled sake is exposed to direct sunlight, its quality deteriorates and its body and flavor are impaired. For this reason, it is recommended to store sake with proper care, in a dark place and at a suitable temperature.