Mureka (stuffy, damp off-aroma)

Mureka (also read as mureko) is a type of deterioration odor that can develop when unpasteurized sake (namazake) is stored at room temperature. The aroma arises when components in the sake change under the influence of oxygen and temperature. Mureka often gives an unpleasant, damp impression and is said to be caused by the activity of yeast and microorganisms. To preserve quality, it is recommended to store the sake at as low a temperature as possible, keep it unopened, and enjoy it early. Sake that shows mureka may already be past its best drinking window, so caution is advised.