Press [Saute] button and add the water and vinegar to the pressure cooker.

When the water comes to a rolling boil, add the bones, onion, ginger, and mushrooms.

Add the bones delicately, so you don't splash yourself with boiling water, by inserting half in the water before dropping it in.

Close the pressure cooker and press [Manual] and leave for the default time (30 minutes) and pressure (high).

When the program is finished let the pressure cooker go into “Keep Warm” mode for 20 minutes, or until the display shows “L00:20.”

Repeat the cooking procedure (Manual Mode default, and Keep Warm for 20 minutes) two more times - for a total cook-and-cool time of 150 minutes.

When the third “Keep Warm” time has gone for 20 minutes, open the pressure cooker, strain the broth and store.