12
Measuring Headspace
Headspace is the air space between the top of the food or its liquid and the lid.
Leaving too much headspace can result in under-processing because it may take
too long to release the air from the jar. Leaving too little headspace will trap
food between the jar and the lid and may result in an inadequate seal.
As a general rule, allow ½-inch headspace for fruits and tomatoes and 1 inch
for vegetables, meats, poultry, and seafood. All recipes will indicate the amount
of headspace necessary for the food being canned.
Removing Air Bubbles
After the food has been packed in the jars, any air bubbles must be removed.
Trapped air bubbles may rise to the top during processing, causing too much
headspace.
Work quickly to remove the air bubbles that have become trapped between the
pieces of food by moving a clean, nonmetallic spatula around the jar between
the food and the side of the jar.
Preparing Jar Rims and Adjusting Lids
Immediately wipe the jar rims with a clean, damp cloth to remove any residue.
Any food particles, such as seeds, grease, or syrup, on the rim of the jar may
prevent the jar from sealing.
Place the flat lid on the rim of the jar, making sure the sealing compound is
touching the glass. Position a band over the lid and, using your fingertips,
screw it onto the jar just until resistance is met (fingertip tight). Do not over-
tighten as air must release from the jars during processing and cooling.
After Processing
Cooling Jars
After processing, remove the jars from the canner and place them on a dry
towel on the counter-top away from drafts. Leave 1 to 2 inches of space
between the jars to allow for even cooling. Do not invert the jars or cover them
with a cloth. Allow the jars to cool naturally for 12 to 24 hours before testing
the seals.
Testing Seals
After the jars have cooled, test the jar lids to be sure a vacuum seal has formed.
Press down on the center of the flat lid to determine if it is concave (stays down
when pressed).
01785 4033-017A CUL English weighted gauge induction canner.indd 12
01785 4033-017A CUL English weighted gauge induction canner.indd 12
12/13/19 10:34 AM
12/13/19 10:34 AM
