1. Not enough time. Under normal circumstances, steamed oysters will open their mouths after they are cooked. If they do not open their mouths, it may be because the steaming time is not enough, and the steaming time needs to be extended.

2. Dead. When the oysters are dead or about to die, they will not open after being steamed because they have lost consciousness, and dead oysters deteriorate quickly, so they should be eaten as soon as possible after steaming and should not be stored.