How to can winter squash (chunks only — NOT purée): time & pressure by the book
Winter squash (chunks only — NOT purée) is low-acid, so pressure canning is the only safe method — here are the USDA processing times and how the pressure changes with elevation.
How long do you can winter squash (chunks only — NOT purée)?
USDA processes winter squash (chunks only — NOT purée) for 55 minutes for pints and 90 minutes for quarts, at the pressure for your altitude and gauge (below). Chunks only — purée NOT USDA-approved.
What pressure for your altitude?
With a weighted gauge, use 10 psi up to 1,000 ft and 15 psi above that. With a dial gauge, use 11 psi to 2,000 ft, 12 psi to 4,000 ft, 13 psi to 6,000 ft and 14 psi to 8,000 ft. Start timing only once the canner has vented 10 minutes and reached pressure.
Why winter squash (chunks only — NOT purée) is pressure canned
Winter squash (chunks only — NOT purée) is a low-acid food (above pH 4.6), so a boiling-water bath cannot reach the temperature needed to destroy Clostridium botulinum spores. It must be pressure canned. Water-bath or “oven canning” a low-acid food is a botulism risk.
FAQ
How long do you can winter squash (chunks only — NOT purée)?
USDA processes winter squash (chunks only — NOT purée) for 55 minutes for pints and 90 minutes for quarts, at the pressure for your altitude and gauge.
Do you water bath or pressure can winter squash (chunks only — NOT purée)?
Winter squash (chunks only — NOT purée) is low-acid and must be pressure canned; a water bath can't make it safe.
What PSI for canning winter squash (chunks only — NOT purée)?
With a weighted gauge, use 10 psi up to 1,000 ft and 15 psi above that. With a dial gauge, use 11 psi to 2,000 ft, 12 psi to 4,000 ft, 13 psi to 6,000 ft and 14 psi to 8,000 ft.
Gear this guide uses
Winter squash (chunks only — NOT purée) can only be made safe in a canner that actually reaches and holds pressure.
- Low-acid foods need the ~240°F only a pressure canner (Presto or All American) can reach — a water-bath canner can't.
- A weighted-gauge regulator can't drift out of calibration, which is why it jumps to 15 psi above 1,000 ft.
- Pack into tested-recipe Ball mason jars and lids and leave the headspace your recipe calls for.
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Sources
General education, not a recipe. Always follow a current USDA-tested process for your food, equipment, and elevation. Processing time per Part 4, Winter squash, cubed — hot pack, sea level.