Hinata-shu (sunlight-struck off-odor)

Hinata-shu (ひなた臭; the source gives the reading as "hinatakusa") refers to a distinctive odor that develops in sake after prolonged exposure to sunlight. It arises when components in the sake are affected by light and heat, causing oxidation and deterioration to progress. Hinata-shu generally gives an unpleasant impression and detracts from the flavor and aroma of the sake, so care is needed in choosing where sake is stored. To prevent it, it is especially important to avoid direct sunlight and to store the sake at an appropriate temperature and humidity.