What causes liquid to be lost from jars during processing?
Loss of liquid may be due to packing jars too full. Headspace must be allowed between the top of the food and lid as specified in the instructions for each food. Food expands when processed, so headspace must be adequate or liquid will be forced out of the jar.
Liquid may be lost if the canner’s pressure fluctuates during processing. Lowering the pressure too suddenly after processing may also cause liquid to be lost. Pressure canner should be removed from the heat and allowed to cool normally at room temperature.
If liquid is lost from jars during processing, can more be added to fill them again?
No, because if the jar is opened and liquid added, this would allow bacteria to enter the jar and you would need to process again.
Loss of liquid does not cause food to spoil, though food not covered by the liquid may darken.
Why does fruit sometimes float in the jar after canning?
Fruit may float because it is packed too loosely, sirup is too heavy, or because some air remains in tissues of the fruit after heating and processing.
How do you test the seal on home-canned foods?
After jars have cooled, check two-piece lids by pressing the center of the flat metal lid; if lid is down and will not move, jar is sealed.