FAQ

Providing that the lid has sealed and you processed the chicken properly, it will be safe despite the loss of liquid.  There are several possible reasons the liquid boiled off:

   1. The jar is packed too full - incorrect headspace.
   2. Starchy foods may absorb some liquid.
   4. The liquid you added to cover cold, raw food was not hot enough when you put it in the canner.
   5. You did not remove air bubbles when you packed the food.
   6. The pressure canner was not sufficiently or properly exhausted (Pressure fluctuated, or temperature lowered suddenly during processing, due to uncontrolled heat source. If the pressure canner cools too quickly while the contents of the jar remain at a much higher temperature, the liquid will boil over. The "coming down" period has to be gradual and even. The petcock was opened before the pressure had returned to zero).
   7. The gauge is inaccurate.  Have it tested at your local Cooperative Extension Office.