Oyster sauce has been used for a long time and is not sealed. It is volatile because of its umami flavor, but the salt is not volatile. Salt will precipitate, and the longer it takes, the saltier it becomes. Many people may put fuel consumption directly on the side of the stove after buying fuel consumption, which is also wrong. There will be a higher temperature near the stove, especially in summer, and the temperature near the stove is higher. Oil consumption cannot be placed in high temperature environment. If oil consumption has been exposed to high temperature environment, it is easy for oil consumption to become moldy, and the moldy oil consumption can no longer be eaten. You'd better put oyster sauce in the cupboard.