One zucchini, two zucchini, three zucchini . . . . four . . .

Summer squash is now in plentiful supply.  When a plant begins to produce, it often produces an overwhelming amount of produce.  While there are several varieties of summer squash, zucchini is the one we hear about the most.  And perhaps the one we have the most ‘fun’ with when surprise care packages show up on co-workers’ desk or neighbor’s doorstep. Before giving all away, consider saving a few for off-season use by preserving.

Summer squash is at its very best when it is eight inches or less in length and an inch or two wide (about two to three days of growth) or, in the case of odd-shapes, picked right when the flower falls off. When picked and eaten at this size, the inside texture is consistent throughout the fruit, never pithy, and the seeds aren’t yet developed. The skin is incredibly tender, and the flavor is mild and sweet–sweet because the plant creates sugars as energy to make seeds; when picked before the seeds develop, those sugars are still present in the flesh. If left on the vine longer, the skin begins to toughen and quality decreases. When cooked the tender squash create uniform, never mushy or stringy, delicious additions to soups, kebabs, sauces, salads, and stir-fries. And, yes, they make a fine zucchini bread or zucchini cake, too.

Fresh squash should be washed in cold water to remove all visible signs of soil before using or storing. Handle carefully as summer squash bruise easily. Store fresh squash in the refrigerator crisper in plastic storage bags or rigid containers to retain moisture. Stored in this manner, squash will maintain quality for 5-7 days. 

So while we know how to use them fresh, what about preserving them?

CANNING
The USDA does not recommend canning summer squash or zucchini alone.  Rather the recommendation is to preserve by freezing, pickling, or drying.  An adequate processing times has not been established for a safe product.  Squash are low-acid vegetables requiring pressure canning to destroy the bacteria that cause botulism. The heat required to can squash results in the squash flesh turning mushy and sinking to the bottom of the canning jar. The compacted flesh does not heat evenly.  Zucchini may only be canned when paired with tomatoes using a tested recipe from The National Center for Home Food Preservation (NCHFP) OR paired with pineapple juice, sugar, and lemon juice for Zucchini Pineapple. Zucchini Pineapple maybe used in salads, desserts, or other recipes calling for crushed or chunk pineapple.

FREEZING
There are three different ways to successfully freeze summer squash./zucchini.  Begin by choosing young squash with tender skin and washing.  There is no need to peel but squash must be blanched before freezing.  Blanching slows or stops the enzyme action which can cause loss of flavor, color and texture.  Blanching also cleanses the surface of dirt and organisms, brightens the color, helps retard loss of vitamins and wilts or softens vegetables making them easier to pack. Blanching may be done in boiling water or steam.

1. Slices – Slice ¼ – ½-inch thick.  Blanch in boiling water for 3 minutes on in steam for 4 1/2 minutes; cool in ice water for at least 3 minutes.  Drain well and package.  If packaged in freezer containers, leave ½-inch of headspace.  Slices may also be flash frozen using the tray method and packaged.
2. Preparation for Frying – Follow instructions for blanching.  Before packaging, dredge in flour or cornmeal.  Flash freeze using the tray method and package.
3. Grated for Baking – While some grate, package, and freeze squash for future baking, it is recommended to steam blanch squash for best quality.  Steam blanch small quantities of grated squash 1 to 2 minutes (until translucent) followed by packing measured amounts into containers.  Cool containers in ice water, seal and freeze.  When ready to use, thaw containers of frozen squash in the refrigerator prior to use. If the squash is watery when thawed, discard the liquid before using in baked goods.

Varieties for freezing include cocozelle, crookneck, pattypan, straightneck, white scallop and zucchini.  Chayote is also regarded as a summer squash but requires slightly different preparation for blanching.  Chayote is diced and seeded before blanching for 2 minutes. 

Remember to label and date packages. Properly packaged and frozen, squash should maintain high quality for approximately 10 months in the freezer.  Vacuum packaging can extend the shelf life of frozen squash but cannot be used as a food preservation method alone. Flash freeze squash slices before packaging, package frozen squash and return frozen squash to the freezer. Vacuum packaged frozen squash will have a longer shelf life than frozen squash which is not vacuum packaged.

PICKLING
Follow a tested recipe for pickling summer squash. Summer squash, zucchini, or chayote work well for pickling.  Two approved and very good tasting recipes can be found at the National Center for Home Food Preservation: Summer Squash Relish  and Pickled Bread-and-Butter Zucchini .

Notes:  Squash may be diced or shredded by hand instead of shredding with a food processor.  Any variety of onion is acceptable.  Celery salt may be used in place of celery seed for a taste preference.  Relish can be enjoyed freshly made without processing.  Fresh or opened jars of relish should be refrigerated. [Preserving Food at Home Resource Guide, PennState Extension, p.104] For best quality and safety, consume refrigerated pickled squash within 7 days.

DRYING
Varieties that work well for drying include zucchini and yellow summer squash.  Wash and trim ends from the squash and cut squash into ¼-inch slices.  Steam blanching slices for 2 ½ -3 minutes or water blanch for 1 ½ minutes is recommended for best quality.  Utah State University Extension suggests adding 1 teaspoon/gallon citric acid to the blanching water to reduce darkening during the drying process.  Drain the slices and arrange them in a single layer on a dehydrator tray. Dry in a food dehydrator at 135-140⁰F for 10-12 hours or until slices are leathery crisp and brittle.  Store the dried pieces in airtight containers (glass jars or in moisture and vapor-proof freezer containers, boxes or bags) in a cool, dry, dark place for up to 12 months. Vacuum packaging dried squash is also an option as it will resist moisture better and extend the shelf life.

Ten pounds of fresh squash will dry to approximately ¾ pound. Dried squash can be used in soups or stews or processed in a food chopper and used in breads or baked goods.

Regardless of how summer squash is preserved or used fresh, it is nutritious. One cup sliced (100 g), fresh summer squash has approximately 18 calories, 1 g fiber, and 1 g protein. Squash is an excellent source of vitamin C. Cooked squash will have essentially the same calories, fiber and protein, but will lose approximately 75% of the Vitamin C during the cooking process.

To learn more about the many uses for summer squash, check out: Summer Squash Is a Versatile Vegetable in Iowa Gardens.

References

• Freezing Summer Squash. National Center for Home Food Preservation.
• P. Kendall, P. DiPersio, and J. Sofos. Drying Vegetables. 2004. Colorado State University.
• B. Nummer.  How to Preserve Summer Squash.  Utah State University, Preserve the Harvest Extension. 
• Preserving Food at Home Resource Guide.  2022. PennState Extension. Code EE0612. 

Updated January 2024. mg.

Marlene Geiger

I am a graduate of the University of Nebraska-Lincoln with a BS in Home Economics Education and Extension and from Colorado State University with a MS in Textiles and Clothing. I enjoy spending time with family and friends, gardening, quilting, cooking, sewing, and sharing knowledge and experience with others.

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