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Reasons for Liquid Loss From Jars

Date: May 1988 (Reviewed June 1996)

Source: University of Wisconsin

As strange as it may seem, there are many reasons for liquid loss from jars during processing. The following are possible reasons:

  1. The jar is packed too full, that is, you did not leave recommended headspace.
  2. The food is packed so tightly that liquid did not fill the spaces between food pieces.
  3. Starchy foods may absorb some of the 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. (You can do this by running a rubber spatula between the food and the jar.)
  6. You did not cover jars of acid foods with one or two inches of water in the boiling water bath canner.
  7. The pressure canner was not sufficiently exhausted.
  8. Pressure fluctuated, or the temperature lowered suddenly during processing, due to uncontrolled heat source.
  9. The temperatures changed suddenly when processing was over. 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.
  10. The petcock was opened before the pressure had returned to zero. When the pressure gets to zero, open the petcock cautiously; if steam escapes, close and wait a few minutes.
  11. The canner stood too long after pressure returned to zero. Open the canner within several minutes after it returns to zero pressure.
  12. You removed the jars too quickly after removing the cover. Let the jars stay in the canner for a few minutes after removing the cover, or until the boiling in the jars goes down.
  13. The gauge's pointer does not rest at zero when not under pressure.

Liquid loss may cause the food to darken, but does not interfere with the keeping qualities. Do not open jars at the end of the processing to replace liquid before you will spoil the food, unless you use the contents immediately.

If you have further questions, contact your county office of the NDSU Extension Service for additional information on canning.

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