Preserve it! Series: Is it Safe to Can Previously Frozen Produce?
Safety and quality depend on what you have in the freezer.
If you’ve got an excess of produce that you don’t have time to process, can you store it in the freezer to can later? Yes, sometimes. The freezing process breaks down the cell structure of produce, which changes the density of the food. For this reason, there are safety or quality issues associated with canning most types of produce. Be sure to know what’s safe for canning, and what the exceptions are.
First, of course, always use a recipe from a reputable source for the product to be canned, and follow all the same instructions as you would when canning fresh produce. One standing exception when canning any frozen produce: Process using the hot pack method only. After freezing, produce isn’t considered “raw” and will likely pack differently in the jar, so choose a recipe that offers a hot pack option. Also, in all cases, fully thaw the frozen produce before canning, and then carefully measure both the solids and the liquid from the frozen product.
Fruit. Frozen fruit, especially for jams and jellies, applesauce, fruit butters, etc., may be safely canned (provided there’s no specific canning exclusion for the fruit).
Tomatoes. Canning previously frozen tomatoes is generally not recommended because of packing, moisture absorption, and heat transfer issues. The best choice, if you do use frozen tomatoes, is to can only well-cooked products such as stewed or crushed tomatoes, tomato juice, or tomato sauce. Canning whole or quartered tomatoes is not recommended. Do not can tomatoes that froze on the vine.
Vegetables. Previously frozen vegetables tend to be softer and can get mushy, so quality-wise, canning them may not be your best bet. Some frozen vegetables should not be canned for safety reasons. These include eggplant, zucchini and all summer squashes, and other vegetables that may break down and become too dense during the canning process.
For further information visit the National Center for Home Food Preservation (NCHFP) or contact your local Cooperative Extension office.
Brought to you by the UC Master Food Preservers of El Dorado County
Last updated July 2025