Does soy sauce have to be refrigerated once the bottle is opened? The answer is no — you don’t need to store an opened bottle of soy sauce in the fridge.
Thanks in large part to its extremely high sodium content, an opened bottle of soy sauce will keep fine for at least a few months at room temperature. As soy sauce manufacturer Kikkoman notes, soy sauce won’t spoil at room temperature, as long as no water or other ingredients have been added to it.
Still, as Kikkoman points out, the shelf life of your soy sauce will be extended if it’s stored in the refrigerator after opening. The bottom line: If you’re a heavy user of soy sauce and tend to go through a bottle fairly quickly, then it’s fine to keep it unrefrigerated. Otherwise, stashing it in the fridge will keep it fresher longer: An opened bottle of soy sauce will usually stay at top quality for at least two years when it has been stored in the refrigerator.
