Prepare Jars: Examine all jars for cracks or chips and discard any damaged jars. Wash jars and rings in hot soapy water, rinse thoroughly, and keep jars hot in a 180°F oven or simmering water until ready to fill.
Heat Lids: Place new canning lids in a small saucepan, cover with hot water at 180°F, and keep hot until ready to use. Do not boil lids as this may damage the sealing compound.
Ready Canner: Add 2-3 inches of water to your pressure canner and place the rack inside. Begin heating the canner while preparing the zucchini to save time during processing.
Prepare Zucchini: Wash zucchini thoroughly and trim both ends. Cut zucchini into uniform slices 1/2 to 3/4 inch thick or dice into 1/2-inch cubes depending on your intended use. Do not peel as the skin helps maintain structure during processing.
Hot Pack Method: Place prepared zucchini in a large pot and add boiling water to barely cover. Bring to a boil and boil gently for 2 minutes to heat through and remove air from tissues. This method produces better texture and color in the finished product.
Fill Jars: Using a slotted spoon, pack hot zucchini pieces into hot jars, leaving exactly 1 inch headspace from the rim. Pack pieces firmly but do not crush or press down as this can prevent proper heat penetration.
Add Liquid and Seasonings: Add salt and lemon juice to each jar if desired, then cover zucchini with boiling water or cooking liquid from the pot, maintaining the 1 inch headspace. Ensure liquid covers vegetables completely but does not exceed headspace requirements.
Remove Air and Seal: Remove air bubbles by running a plastic tool around the inside of each jar, adjusting liquid level as needed to maintain proper headspace. Wipe jar rims thoroughly with a clean, damp cloth and center hot lids on jars with rings finger-tight only.
Load Canner: Place filled jars on the canner rack using a jar lifter, ensuring jars do not touch each other or the sides of the canner. Lock canner lid in place and heat on high until steam vents steadily for 10 minutes to purge air from canner.
Process Under Pressure: Place pressure regulator on vent and process at 11 pounds pressure for 30 minutes for pints or 40 minutes for quarts. Adjust pressure for altitude: 1,001-2,000 feet use 11 lbs, 2,001-4,000 feet use 12 lbs, 4,001-6,000 feet use 13 lbs, 6,001-8,000 feet use 14 lbs. After processing, turn off heat and let pressure return to zero naturally before opening canner.
