1. Add white vinegar: The sour taste of white vinegar can make the sour taste of pickles more obvious. You can add it according to your personal taste, but be careful not to add too much, otherwise it will be too acidic.

2. Add Chinese cabbage: Chinese cabbage can help kimchi to ferment again, making kimchi more sour. You can cut the cabbage into pieces and put it in a container. Try to fill all the space. If it is not easy to put it, you can cut some cabbage. At the same time, pour in some boiling water to help the cabbage and kimchi ferment again.

3. Make kimchi again: If the above methods can't solve the problem, it is recommended to make kimchi again. When making kimchi, we should pay attention to the amount of salt, the degree of sealing and the time to ensure that kimchi can be fermented successfully.