Despite what you may have heard, canning squash is possible, but certain squash types require special steps. According to the USDA, summer squash, such as zucchini and yellow squash, are low-acid foods requiring pressure canning for a specific time to create enough heat to kill the bacteria that causes botulism.
The problem the USDA faces is there isn’t enough information currently available to determine the correct processing times for canned squash. Cooked summer squash becomes soft, and when placed into jars, it mushes together.
The densely packed squash affects the way the jar heats and influences the processing time. To successfully can summer squash, it must be pickled or used in other canning recipes with highly acidic foods.
While it’s not recommended to pressure can plain summer squash, winter squash is a different story. Continue reading to find out how to can squash with a pressure cooker and water bath canner.
How to Safely Can Squash for Long Term Storage
Pressure canning and water bath canning summer squash might not work, but pickling certainly does. Discover how to preserve summer and winter squash using different methods.
How to Can Squash in a Pressure Canner
When it comes to canned squash, winter squashes like butternut, acorn, and spaghetti squash are the safest choices. The best part is most winter squashes require the same steps, so it’s one basic recipe for you to follow when you preserve vegetables like squash.
Using your preferred type of squash, wash the outside and cut in half and remove the seeds and peel. Steam it until tender and then cut into one-inch cubes.
Place them into Mason jars, but do not pack the jars full. Cover the cubed squash with boiling water and leave one-inch headspace. Secure the canning jars finger tight with lids and rings.
Place the jars inside a pressure canner and close the lid. The pressure for up to 1,000 feet above sea level is 10 pounds pressure; anything higher than that requires 15 pounds pressure—process pint jars for 55 minutes and quart jars for 90 minutes.
Best Method for Canning Summer Squash
While pressure canning is out for low-acid vegetables, you can turn your abundance of zucchini into pickles or use it while canning fresh tomatoes.
With pickling, you can find refrigerator type recipes, but this one requires using a water bath canner to extend the shelf-life of zucchini pickles.
Add some water to a bowl, then drop in the onions and zucchini slices. Sprinkle in salt and then stir until dissolved. Soak the veggies in the salted water for two hours before draining. Place drained vegetables into a glass or other heatproof bowl.
Add vinegar, sugar, both types of mustard, turmeric, and celery seeds to a saucepan and bring the liquid to a boil. Pour the mixture into the onion and zucchini slices and let soak for two hours.
Pour everything into a bigger saucepan and bring it to a boil and cook for three minutes. Transfer zucchini and onions into hot jars and fill with pickling liquid.
Use a thin stick or knife to remove air bubbles and refill jars as needed with juice. Only leave ¼ inch of headspace. Wipe the rims and then secure jars with lids and rings until finger tight.
Transfer jars into a water bath canner, making sure to leave two inches between each jar—cover jars with one inch of water. Boil the water and cover and process for 10 minutes.
Is Canning Squash in a Water Bath Possible?
Water bath canning squash doesn’t work, due to its low acidity. The only way to safely use a water bath canner for canning squash is through pickling it or turning it into a relish.
Place the green pepper, onions, and squash into a bowl, and sprinkle everything with the salt. Toss everything and let stand in the refrigerator for 12 hours. Remove from the refrigerator and drain off any liquid. Rinse and drain the vegetables and set aside.
Use a Dutch oven and bring the seasonings, vinegar, and sugar to a boil. Add the vegetables and then return to a boil, allowing the squash mixture to gently simmer for 15 minutes before removing from the heat.
Ladle the hot squash mixture into pint-sized jars, leaving a ½ inch headspace. Use a butter knife or thin stick to remove any air bubbles and ladle in more relish as needed. Clean the rims of each jar and then secure them with a lid and ring.
Place jars into the canner and fill until water is one inch above the jars. Bring it to a boil, cover the canner, and process relish for 15 minutes.
Remove jars from the hot water, and set aside on towels to cool. Listen for sealing of jars – any jars that fail to seal require refrigeration.
Can I Mash or Puree Squash Before Canning?
Based on what the National Center for Home Food Preservation suggests, do not mash or puree any squash before canning. You cannot safely can mashed or pureed squash, including pumpkin, because the amount of squash varies significantly from one batch to another.
The variation in the amount of mashed or pureed squash in the jars makes it harder to create an accurate processing time. Exact processing times are necessary to kill any bacteria in the food to ensure it is shelf-stable.
How to use Canned Squash
There are a few ways to use canned squash. Sautéing canned squash in some butter or oil with a little seasoning is a quick side dish that goes well with most dinners.
You can also bread and fry pickled summer squashes – just use a basic pickling recipe instead of one with a variety of seasonings. Another great way to use it is in a squash casserole. We included one of our favorite recipes.
Heat the canned butternut squash until soft enough to mash. Add the squash, milk, vanilla extract, white sugar, eggs, flour, and ¼ cup melted butter into a casserole dish. Use a wooden spoon to mix everything. Place inside a 425°F oven and cook for 45 minutes.
Mix the remaining ingredients. Sprinkle the topping over the cooked casserole. Place back inside the oven to allow the topping to brown and then serve.
Thank you for reading our post on how to can squash safely. If you found any of our canned squash recipes or tips useful, please take a minute to share our secrets for canning squash with others on Facebook and Pinterest.