Canning 101...Who Cares About Headspace?

     The space in the canning jar from the underside of the lid to the top of the food or liquid in the jar is called the headspace.  Too little headspace, and the food may bubble over during processing.  The residual food may interfere with the seal of the lid, not to mention making a mess in the canner.  Too much headspace and the food at the top may discolor in storage.

     Too little headspace is usually my problem if I'm going to have one.  There's nothing worse than canned salmon over flowing it's jar in the pressure canner!  Learning where the headspace is on your jar really helps a lot.





Turn your jar to where the threads "overlap".
That is not necessarily the front of the jar.









1/4 inch is at the first thread.
1/2 inch is at the middle thread.
1 inch is just below the "finish". (just below that last "thread")
1 1/4 inches is halfway down the shoulder.
1 1/2 inches is just below the shoulder.



     When you are using your jar filler, get used to where these marks are on your filler.  On my filler, just to the bottom of it is 1 inch.  The more you can, knowing where your headspace marks are, just comes naturally.

     Different foods have different headspace because of how that food expands or doesn't expand in the jar.  Your recipe usually tells you how much headspace you should leave.  When I can foods to compete at my county fair, headspace is very important to the judge.  The wrong headspace will be disqualified right away.  These are the headspaces required for our fair, and in general, what you should use for everyday canning.

Jams and Jellies.......1/4 inch
Pickles......................1/2 inch
Fruits........................1/2 inch
Tomatoes.................1/2 inch
Vegetables...............1 inch
Meats.......................1 to 1 1/2 inches


Read the rest of the series (just getting started):
Canning 101 -- Why 2-Piece Lids?

.....jean

Linked To: Farmgirl Friday Blog Hop
Linked To: Homestead Barn Hop