Quick Answers

Reasons for Liquid Loss From Jars

There are many reasons for loss of liquid from jars during processing:

1. Leaving wrong amount of headspace when filling jars. Leave:

1 inch headspace for LOW ACID foods such as most meats and vegetables.
1 ¼ inch headspace for chicken and rabbit.
½ inch headspace for HIGH ACID foods such as fruits, tomatoes, and fruit juices.
¼ to ½ inch headspace for pickles and relishes as directed.
¼ inch headspace for jams and jellies.
Check USDA instructions for each food.

2. Food packed so tightly that liquid did not fill the spaces between pieces of food.
3. Starchy foods may absorb some of the liquid.
4. Liquid added to cover cold raw food was not hot enough when placed in canner.
5. Air bubbles not removed at time of packing. Use a plastic spatula around the inside of the jar to remove air bubbles.
6. Jars processed in boiling water bath not covered with 1-2 inches of water.
7. Pressure canner not sufficiently exhausted.
8. Allowing pressure to fluctuate or sudden lowering of temperature during processing.
9. Too sudden changes in temperature when processing period is over. (If the canner cools too quickly while the contents of the jar remain at a much higher temperature, the liquid will boil over. The contents of the jar and the canner have to cool down gradually from 240°F to 212°F. The "coming down" period should be gradual and even.)
10. Opening the petcock before the pressure has returned to zero. (When the pressure has returned to zero, open the petcock very cautiously and if steam escapes, close and wait a few minutes. This avoids cooling the atmosphere around the jars too fast which causes liquid to boil over.)
11. Letting the canner stand too long after pressure returned to zero. It should be opened within a couple of minutes after it returned to zero pressure.
12. Removing the jars too quickly after removing the cover. Let the jars remain in the canner a few minutes after removing the cover, or until the boiling in the jars is less vigorous.
13. Having an inaccurate dial pressure gauge that does not return to zero. (The petcock in this case could be opened too soon or not soon enough.)
14. Not removing particles of food, seeds, seasonings, or pulp of fruit from top of jar or threads with damp paper towel before putting on lid. Particles left on rim of jar can because of lid sealing, then loosening..
15. Screwing band too tight can cause lid to buckle. A band MUST be tight enough to hold the rubber sealing compound closely against the top of the jar. However, if the band is forced as far as it can be turned with a strong hand, the jar cannot vent. When the jar can't vent, pressure within the jar causes the lid to buckle. We suggest you tighten bands comfortably tight to prevent buckled lids.
16. Not screwing band tight enough. As in No. 16, we suggest you tighten band comfortably tight so rubber sealing compound will be held closely against the top of the jar.
17. Insufficient heat to seal the lid such as "open kettle". Do follow recommended processing times and methods.
18. Leakage of steam from pressure canner.

Loss of liquid may cause the food to darken, but does not interfere with the keeping qualities unless the liquid that has been lost has caused food, grease or seeds to lodge under the lid and prevented a seal from forming. If liquid has been lost, do NOT open jar at the end of the processing to replace liquid. Opening the jar will result in spoilage of the food unless you use the contents immediately.

NOTE: Fruit packed raw must have 1 ½ inch of space for syrup - fruit juice cooks out of fruit, and fills jar with liquid. Otherwise too much liquid will boil over and siphoning will cause loss of liquid and possible sealing failures.

For more information on any of the above situation you may have questions on or need more information, please call the Whatcom County Cooperative Extension at 360-676-6736.

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