Canning Pumpkin (What’s Safe)

We research products independently. When you buy through links on this page, we may earn a commission from Amazon at no extra cost to you. As an Amazon Associate we earn from qualifying purchases. Learn more.

The only safe way of canning pumpkin at home is as 1-inch cubes in a pressure canner. The National Center for Home Food Preservation (NCHFP) process is 55 minutes for pints and 90 minutes for quarts, with 1 inch of headspace. At 0 to 1,000 feet, run a weighted-gauge canner at 10 psi. A dial-gauge canner runs at 11 psi up to 2,000 feet.

There is no tested process for pumpkin purée, mashed pumpkin, pumpkin butter or pumpkin pie filling. The NCHFP says home canning is not recommended for mashed or pureed pumpkin. It also says it has "no recommendation" for pumpkin butter and does not "make up or estimate" low-acid processes. We won't give you one either. Freeze those products instead.

Why Pumpkin Purée Can't Be Canned

The USDA used to publish directions for canning mashed winter squash. According to the NCHFP, those directions were withdrawn after expert review when the USDA Complete Guide to Home Canning came out in 1989. They're now considered out of date.

The reason is how heat moves through the jar. Studies at the University of Minnesota in the 1970s, cited by the NCHFP, found too much variation in thickness between batches of pumpkin purée to calculate one processing time that would cover them all. The NCHFP lists thickness, acidity and available water as the factors that are critical to the safety of canned pureed pumpkin. A time that works for one batch can't be assumed to work for the next.

That matters because pumpkin is a low-acid food (pH above 4.6). The NCHFP says it can support the growth of Clostridium botulinum, the bacterium that causes botulism, if spores survive processing. No one has funded the research for a new home process since then.

Cubes are different. The NCHFP says the USDA process should be used only with squash cut into 1-inch cubes, because that's the product it was set for.

What You Can and Can't Can

The same rules apply to winter squash such as butternut, acorn and hubbard. The NCHFP covers pumpkin and winter squash in one recipe.

Pressure Canning Pumpkin Cubes: Times and Pressure

Dial-gauge pressure canner

Weighted-gauge pressure canner

The dial-gauge table stops at 8,000 feet. If you live higher, ask your county extension office. Our pressure canning altitude chart explains the bands.

Choosing Pumpkins

The NCHFP asks for pumpkins and squash with a hard rind and stringless, mature pulp of ideal quality for cooking fresh. It says small sugar or pie pumpkins make better products than large carving types.

How much you need: about 16 lb for a 7-quart canner load, or 10 lb for 9 pints. That's roughly 2¼ lb per quart.

Step-by-Step: Canning Pumpkin Cubes

1. Wash the pumpkin and remove the seeds.
2. Cut it into 1-inch-wide slices and peel them.
3. Cut the flesh into 1-inch cubes. Keep them close to that size; the time was set for 1-inch pieces.
4. Boil the cubes for 2 minutes in water.
5. Don't mash or puree.
6. Fill hot jars with the cubes and the cooking liquid, leaving 1 inch of headspace.
7. Release air bubbles, recheck the headspace, wipe the rims and put on the lids.
8. Load the canner with the rack and 2 to 3 inches of hot water (or the amount in your manual). Lock the lid.
9. Vent for 10 minutes, then put the weight on or close the petcock.
10. Bring it to the pressure for your elevation and time 55 minutes for pints or 90 for quarts. If the pressure falls below the target, bring it back up and restart the full time.
11. Let the canner depressurize on its own. Remove the weight, wait 10 minutes and open the lid away from you.
12. Cool the jars 12 to 24 hours, then check the seals.

If you're new to pressure canning, our beginner's guide to using a pressure canner covers venting and cool-down in detail.

Turning Canned Cubes Into Purée and Pie

This is the safe workaround. Can the cubes, then make purée when you need it.

• For pie: the NCHFP says to drain the jars and strain or sieve the cubes. Mash or blend them, then use them like fresh purée.
• For soup: drain, purée with broth and add cream or milk while it cooks.
• For pumpkin butter: cook the drained, mashed cubes with sugar and spices, then refrigerate it or freeze it. Don't can it.

Freezing Pumpkin Purée

When you want purée ready to go, freezing is the method the NCHFP points to: pureed or mashed pumpkin can be frozen for long-term storage. Its freezing directions are short:

1. Choose full-colored, mature pumpkin with a fine texture. Wash it, cut it into cooking-size pieces and remove the seeds.
2. Cook until soft in boiling water, in steam, in a pressure cooker or in the oven.
3. Scoop the pulp from the rind and mash it.
4. Cool it quickly by setting the pan in cold water and stirring now and then.
5. Pack it into freezer containers, leaving ½ inch of headspace. Seal and freeze.

Pumpkin in Canned Soup

The NCHFP soup procedure covers soups made from ingredients that each have their own canning recommendation, so pumpkin or winter squash cubes can go into a chunky vegetable soup. The rules:

• Prepare each ingredient as its own recipe describes, then combine with broth, tomatoes or water and boil for 5 minutes.
• Fill jars only halfway with solids, then top up with liquid, leaving 1 inch of headspace.
• Don't add noodles, pasta, rice, flour, cream, milk or other thickeners.
• Process 60 minutes for pints and 75 for quarts (100 minutes if the soup contains seafood).

A smooth, puréed pumpkin soup doesn't fit this procedure. Can the soup chunky and blend it when you reheat it.

Common Mistakes When Canning Pumpkin

• Canning purée because "Grandma did." Old USDA directions were withdrawn in 1989. A jar that looks and smells fine can still carry botulinum toxin; our botulism safety guide explains why.
• Water bath canning pumpkin. Pumpkin is low-acid. Our guide to pressure canning vs water bath canning explains which foods need which method.
• Cutting bigger cubes. The process was set for 1-inch cubes.
• Mashing the cubes in the jar. Keep them as pieces.
• Adding sugar, spices or butter. None are in the tested recipe.
• Dry canning. The NCHFP says vegetables canned without the covering liquid used in the research may be under-processed, with a risk of botulism.

For other squashes, sweet potatoes and root vegetables, see our canning vegetables chart. If you still need a canner, our best pressure canner guide compares sizes.

Storing Canned Pumpkin

Remove the bands, check that each lid is concave and holds, and store the jars in a cool, dark, dry place. The USDA says below 95°F (35°C), ideally 50 to 70°F (10 to 21°C).

The CDC recommends boiling home-canned low-acid foods before eating: 10 minutes below 1,000 feet, plus 1 minute for each additional 1,000 feet. Never taste pumpkin from a jar with a bulging or unsealed lid, spurting liquid, mold or an off smell.

FAQ