Why is Liquid lost during the canning process

This is one of the most common questions of every food preserver is why am I losing liquid from my jars.

The answer is that it could be any one of these things.

1:  Raw Packing instead of Hot Packing often leads to water loss because the food has air in it and that air is driven from the jars during the canning process.  This is why it recommended that you hot pack your foods.  Fruits especially have this problem.

2:  Rapid change in temperature in your canner.  Keep your boiling water canner at a steady boil and if using a pressure canner, lower your temperature to maintain the pressure, but don't let the pressure keep going up and down.  Get it gently rocking and keep it steady.

3:  Removing jars too quickly from a canner causes  stress on the jars and they lose liquid.  This is one reason you should always turn off the heat, remove the lid and wait at least 5 minutes before taking jars out of the water bath canner or 10 minutes for a pressure canner.

Reference:  PennState Extension