Translations:AY Honors/Food - Canning/Answer Key 2/19/en
From Pathfinder Wiki
Sealing
Place the lid on top of the jar, making sure that the rubber seal on the underside of the lid comes in contact with the mouth of the jar. Then screw the threaded portion of the lid on over it. It only needs to be tight enough to hold the rubber seal to the mouth of the jar. The actual seal occurs because the air inside the jar shrinks as it cools, and this actually pulls the underside of the lid inward. Of course this only works if the food is hot when you pour it into the jar.
