Butternut squash is a mildly sweet, versatile winter squash. Its deep orange color and flavor is reminiscent of pumpkin, and it's often used as a substitute for pumpkin in pies and soups. Preserving the garden bounty of squash in fall is simple with a pressure canner. Preserve the squash in chunks, as mashed squash is too dense to heat properly during the canning process and may lead to harmful bacteria surviving the process.
Wash one-pint canning jars, lids and rings in warm, soapy water. Rinse away the soap residue, then place the jars in hot water until ready to use.
Cut off the top and bottom of the squash. Peel the skin off the squash with a serrated vegetable peeler.
Cut the squash in half. Scoop out all the seeds and pulp with a spoon.
Cut the squash into 1-inch cubes. Place the cubes in a pot and add enough water to cover. Boil the cubes for 2 minutes.
Fill the jars with the butternut cubes to within 1 inch of the rim. Add the cooking liquid to the jar to fill in around the squash cubes, leaving the 1 inch headspace between the top of the liquid and the jar rim.
Wipe of the rim of the jar with a clean cloth, then set a canning lid on top. Secure the lid to the jar with a clean canning ring.
Place the jars into the pressure canner, making sure the aren't touching. Add the amount of water indicated in your canner's instruction manual, then secure the lid.
Process the pint jars of squash for 55 minutes at 11 pounds. If your altitude is above 2,000 feet, process at 12 pounds. Over 4,000 feet, process at 13 pounds.
Remove the lid from the canner once pressure returns to zero on the dial. Lift the jars out of the canner with a jar lifter and set them on a rack to cool for 24 to 48 hours. Store the jars for up to one year in a cool place out of direct light.