Low-Acid Foods Step 5 

Pack food into a hot jar leaving 1 inch (2.5 cm) headspace. This is the space at the top of the jar between the underside of the sealing disc and the top of the food or liquid. Over-filling and under-filling can result in seal failure.

Remove air bubbles by sliding a nonmetallic utensil such as a Bubble Remover or rubber spatula between jar and food. After removing air bubbles, readjust head space if required.

Wipe jar rim removing any food residue.

Centre hot sealing disc on clean jar rim.

Apply screw band – screw band down until resistance is met, then increase to fingertip tight. Return filled jar to rack in canner. Overtightening prevents venting--air escaping--during heat processing and can cause seal failure. The "steam" created inside the jar during heat processing must be exhausted to allow the formation of a strong airtight seal.

Place jar on rack in canner. When all jars are filled or canner is full, check that water level in canner is about 3 inches (8 cm) or that recommended in pressure canner manufacturer's manual.

Lock canner lid in place, leaving vent open. Place canner over high heat. Allow steam to escape steadily for 10 minutes (venting canner). Close the vent, using the weight or method described for your canner. Gradually reduce the heat to achieve and maintain the recommended pressure. Regulate heat only with gradual changes to heat level.

When processing time is complete, remove canner from heat. Let canner stand undisturbed until pressure drops to zero.

When dial gauge registers zero or when no steam escapes when weighted gauge canner's weight is nudged, wait 2 minutes - then remove cover, tilting it away from yourself.