1. Wash the ribs and chop them into pieces. Wash the yam and carrots and cut them into pieces.

2. Put cold water in the pot, put the ribs in, skim off the floating foam after boiling, put the skimmed water and ribs in the pressure cooker, and put a proper amount of vinegar.

3. Pour in the yam and ribs, too.

4. Depending on the situation, whether to add water or not, press the stew button.

5. After stewing, put the right amount of salt to the pot.