Pumpkin and winter squash cubes, pressure canned
The only safe way to put squash in a jar: firm cubes in water, which you drain and mash the day you bake the pie.
Makes
About 9 × 500 ml (pint) jars from 4.5 kg (10 lb) of squash, or 7 × 1 L (quart) jars from 7.3 kg (16 lb)
Active time
1¼ hours
Total
3½ hours including venting, processing and cooling the canner
Before you start
What keeps this jar safe
- Purée cannot be canned at home, full stop. Mashed pumpkin is so thick that heat crawls to the centre of the jar unevenly, and tests at the University of Minnesota found batch-to-batch thickness varied too much for any single time to cover. No research has established a safe home-canning time, so none exists — for purée, pumpkin butter or pie filling.
- Cubes only, 2.5 cm (1 inch), boiled just 2 minutes so they stay firm and the water can move between them.
- Pressure canner only; this is a low-acid vegetable, and adding sugar, vinegar or lemon does not change that.
- Mash after you open the jar: drain the cubes, press through a sieve or mash, and use as you would canned pumpkin.
- For a smooth product that keeps, freeze it instead — see frozen squash purée.
This follows NCHFP: Pumpkins and winter squash — cubed. Quantities, acid and times are theirs; do not scale the vegetables without scaling everything, and do not change the vinegar, lemon juice or processing time.
Ingredients
- 7.3 kg (16 lb) hard-rinded pumpkin or winter squash for 7 L jars — 4.5 kg (10 lb) for 9 × 500 ml jars; about 1 kg (2¼ lb) per litre jar. Pie pumpkins, butternut and buttercup work better than jack-o’-lantern types
- Water for boiling and covering
Processing
- Jars
- 500 ml (pint) · 1 L (quart) in brackets
- Headspace
- 2.5 cm (1 inch)
- Time at 0–300 m (0–1,000 ft)
- 55 min at 10 psi (weighted gauge)
- Higher up
- 1 L jars: 90 min. Weighted gauge: 10 psi at 0–300 m (0–1,000 ft), 15 psi above 300 m. Dial gauge: 11 psi at 0–600 m (0–2,000 ft), 12 psi at 600–1,200 m, 13 psi at 1,200–1,800 m, 14 psi at 1,800–2,400 m. Processing time does not change with altitude for pressure canning — only the pressure does.
Method
- 1
Start the pressure canner heating with 5–7.5 cm (2–3 inches) of water. Wash the jars and keep them hot.
- 2
Wash the squash, split it and scoop out the seeds (save them to roast — a child’s job). Cut into 2.5 cm (1 inch) wide slices, peel each slice, then cut into 2.5 cm (1 inch) cubes.
- 3
Put the cubes in a pot, cover with water, bring to the boil and boil 2 minutes. Do not cook them soft and do not mash.
- 4
Fill the hot jars with the cubes and the cooking liquid, leaving 2.5 cm (1 inch) headspace. The cubes should stay whole and swim in liquid.
- 5
Free the air bubbles, wipe the rims, centre the lids and tighten the bands fingertip-tight. Set the jars on the rack.
- 6
Lock the lid, vent steam for 10 minutes, then weight the vent and bring to 10 psi weighted or 11 psi dial at 0–300 m.
- 7
Time once at pressure: 500 ml jars 55 minutes, 1 L jars 90 minutes. Keep the pressure steady; if it falls below target, bring it back and start the full time again.
- 8
Cool the canner naturally to zero, remove the weight, wait 10 minutes, open the lid away from you and lift the jars onto a towel. Leave 12–24 hours before checking seals.
Keeps: Best within 12 months. Drain and mash on the day you use it. Refrigerate after opening and use within 3–4 days.
Variations: Any hard winter squash — butternut, buttercup, hubbard, kabocha — cans the same way. Spaghetti squash is a poor choice because it falls into strands.
Tested source: NCHFP: Pumpkins and winter squash — cubed. Checked October 2026. If a jar did not seal, refrigerate it and use it within a few days. Never taste anything from a jar that is bulging, leaking, spurting or smells wrong — when in doubt, throw it out without tasting.
The crop
Pumpkins: when to pick, how to store, what else to make →
The best thing to do with a pie pumpkin is leave it whole on a cool shelf until you want it, then roast it and freeze the purée in 500 ml tubs with 1 cm of headspace — one tub is one pie. The seeds are the second crop: rinse the strings off, dry them for a few hours, toss with oil and salt, and roast at 150 °C (300 °F) for 10–15 minutes, stirring. What does not work is canning purée, pumpkin butter or pumpkin pie filling: no tested home process exists for any of them, because a dense purée does not heat through to the centre of the jar in any predictable time, and this is a botulism question, not a texture one. The only jar form is 2.5 cm (1 in) cubes, boiled two minutes and pressure-canned 55 minutes for 500 ml jars or 90 minutes for litre jars at 10 psi (weighted gauge) near sea level, to be mashed after opening. There is no water-bath method. A carving pumpkin can be cooked, but the flesh is watery and stringy; use it for soup or feed it to the compost and grow a pie pumpkin for the kitchen.
More for pumpkins
- Freezing
Roasted squash and pumpkin purée, frozen
The safe way to put up smooth pumpkin for pie, soup and muffins — in the freezer, in the amounts your recipes call for.
A 2 kg butternut or pie pumpkin gives about 1 L of purée, four 250 ml portions · 30 minutes active
The recipe →