Pumpkin is a low-acid vegetable and requires special attention to preparation and processing. Pumpkin butters and pumpkin preserves are popular, but they cannot be safely canned for room-temperature storage. The only directions for canning pumpkin and winter squash are for cubed pulp.
Canning cubed pumpkins
■ Only pressure-canning methods are recommended for canning cubed pumpkin. All low-acid foods, including pumpkin, must be canned using tested pressure-canning processes. An average of 16 pounds of cubed pumpkin is needed for a canner load of 7 quarts; an average of 10 pounds is needed for a canner load of 9 pints — an average of 2¼ pounds a quart.
■ Pumpkins and squash should have a hard rind and stringless, mature pulp of ideal quality for cooking fresh. Small pumpkins (sugar or pie varieties) make better products. Wash the pumpkins, remove seeds, cut into 1-inch-wide slices, and peel. Cut flesh into 1-inch cubes. Boil 2 minutes in water. Caution: Do not mash or purée. Fill jars with cubes and cooking liquid, leaving 1-inch head space. Adjust lids and process following the U.S. Department of Agriculture recommendations at Homefoodpreservation.com.
Freezing is the easiest way to preserve pumpkin, and it yields the best-quality product. Select a full-colored mature pumpkin with fine texture. Wash, cut into cooking-size sections and remove seeds. Cook until soft in boiling water, in steam, in a pressure cooker or in an oven. Remove pulp from rind, and mash. To cool, place pan containing pumpkin in cold water and stir occasionally. Pack into rigid containers, leaving head space, and freeze.
Drying pumpkin and pumpkin seeds
■ Wash and peel pumpkins, and remove fibers and seeds from the flesh. Cut into small, thin strips. Blanch strips over steam for 5 to 6 minutes and cool rapidly. Dry the strips in a dehydrator until brittle. Pumpkin makes excellent dried vegetable leather. Purée cooked pumpkin and strain. Add honey and spices, then dry on a home food dehydrator tray.
■ Drying seeds and roasting seeds are different processes. To dry, carefully wash pumpkin seeds to remove the clinging fibrous pumpkin tissue. Pumpkin seeds can be dried in the sun, in a dehydrator set at 115 to 120 degrees for 1 to 2 hours, or in an oven on warm for 3 to 4 hours. Stir them frequently to prevent scorching.
■ To roast, take dried pumpkin seeds, toss with oil and/or salt, and roast in a preheated oven at 250 degrees for 10 to 15 minutes.
Source: USDA's 'Complete Guide to Home Canning'