Wash canning jars in hot soapy water and rinse thoroughly, then keep hot in a 180°F oven or hot water until ready to fill. Place new lids in a small saucepan, cover with water, and heat to 180°F (do not boil).
Fill your boiling water bath canner with enough water to cover jars by 1-2 inches and bring to a rolling boil. Maintain boiling throughout the process.
Remove crown, peel, and core from pineapples using a stainless steel knife, then cut into 1/2-inch thick slices or bite-sized chunks, discarding any bruised or damaged portions.
Pack pineapple pieces firmly into hot jars, leaving exactly 1/2 inch headspace at the top of each jar.
Add 2 tablespoons of bottled lemon juice to each pint jar or 1 tablespoon to each half-pint jar to maintain safe acidity levels.
Cover pineapple with boiling water or hot light syrup, maintaining the 1/2 inch headspace and ensuring all fruit pieces are completely covered with liquid.
Remove air bubbles by sliding a plastic bubble removal tool around the inside of each jar, then adjust liquid levels if needed to maintain proper headspace.
Wipe jar rims clean with a damp cloth, place hot lids on jars, and apply screw bands fingertip tight (do not overtighten).
Using a jar lifter, carefully place filled jars on the canner rack and lower into the boiling water, ensuring water covers jars by 1-2 inches.
Process pint and half-pint jars for exactly 20 minutes in a rolling boil (add 5 minutes for altitudes 1,001-3,000 feet, 10 minutes for 3,001-6,000 feet, 15 minutes for altitudes above 6,000 feet), then turn off heat and let jars sit in canner for 5 minutes before removing to cool on a towel-lined counter for 12-24 hours.
