After opening a bottle of sake, it is best consumed within two or three hours. It is possible to store sake in the refrigerator, but it is recommended to consume it within two days. When premium sake is opened it begins to oxidize, which affects the taste. If the sake is kept in the refrigerator more than three days, it will lose its "best" flavor. This does not mean it should be disposed of if not consumed. Generally, sake can keep very well and taste good after weeks in the refrigerator. How long a sake will remain drinkable depends on the quality of the product, and whether it is sealed with a vacuum top to decrease oxidation.