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In this method, you also preserve food in glass jars with two-piece lids. Pressure canning must be used for low-acid foods and involves using an appliance called a—what else?—“pressure canner” to achieve a temperature of 240 degrees Fahrenheit, which is substantially higher than the 212 degrees that the water-bath method can achieve and is sufficient to kill both microorganisms and their spores, including botulism, to which low-acid foods are vulnerable. As with water-bath canning, subsequent cooling creates a vacuum seal, which prevents air and microorganisms from entering and causing spoilage. This is the only safe way to can low-acid foods such as vegetables, meats, and seafood because of their susceptibility to botulism.

Pros: Pressure canning can also be used for high-acid foods such as tomatoes to lower the processing time. The electricity consumption for processing is moderate and there’s no cost for storage.

Cons: The initial investment for a pressure canner is somewhat costly. In addition, foods experience some flavor and nutrition loss compared to freezing. Pressure canning takes longer and is slightly more complicated than water-bath canning and freezing.

Corn is one of many vegetables that should be pressure-canned. To can corn, you’ll need to cut it off the cob (individual recipes will explain how to do this).

FOLLOW THE RULES

Be sure to follow the recipes exactly, without adjusting the ingredients, proportions, type of processing, or processing time. For extra guidance, check with your local Cooperative Extension Service or USDA Guides to Home Canning and Preserving.