Freezing is the best option for safely preserving zucchini.
At a recent food preservation class, the topic of preserving zucchini was discussed. Participants asked why canning zucchini was not recommended. Recommendations for canning summer squashes, including zucchini that you may have seen in past United States Department of Agriculture (USDA) bulletins, have been withdrawn due to uncertainty about the determination of processing times. Squashes are low-acid vegetables and require pressure canning for a known period of time that will destroy the bacteria that causes botulism. Documentation for the previous processing times cannot be found and reports that are available do not support the old process. Slices or cubes of cooked summer squash will get quite soft and pack tightly into the jars. The amount of squash filled into a jar will affect the heating pattern in that jar.
Michigan State University Extension recommends that to preserve zucchini (and all summer squash) you should freeze it. Freezing zucchini is easy to do by following the recommendation below:
- Choose young squash with tender skin
- Wash and cut in half-inch slices
- Water blanch for three minutes. Cool promptly, drain and package, leaving half-inch headspace.
- Seal, label and freeze
Also the zucchini can be grated (for baking) and frozen by following the recommendation below:
- Choose young tender zucchini
- Wash and grate
- Steam blanch in small quantities one to two minutes until translucent
- Pack in measured amounts into containers, leaving half-inch headspace. Cool by placing the containers in cold water.
- Seal, label and freeze
If the zucchini is watery when thawed, discard the liquid before using the zucchini.
One zucchini product you can safely preserve by canning is zucchini pineapple. Follow the tested, research based recipe below from the National Center for Home Food Preservation:
- 4 quarts cubed or shredded zucchini
- 46 ounces canned unsweetened pineapple juice
- 1 ½ cups bottled lemon juice
- 3 cups sugar
Peel the zucchini and cut into half-inch cubes or shred. Mix zucchini with other ingredients in a large saucepan and bring to a boil. Simmer for 20 minutes and then fill jars with hot mixture and cooking liquid, leaving half-inch headspace. Adjust lids and process half-pint or pint jars for 15 minutes in your water bath canner. After processing, label and date your jars before storing.
Enjoy your zucchini this summer then freeze it or can zucchini pineapple to enjoy during the winter months. For more about home food preservation enroll in MSU Extension’s online home food preservation course.