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"What are basic home canning instructions?"

Hi Anne and Sue,

I'm trying my hand at canning and have frequently seen the phrase "process according to instructions." What's processing? And where do I find these basic instructions?

Thanks, Isabel


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Dear Isabel,

The term "processing" refers to methods of heating foods after packing them into preserving jars. Heat processing is key in keeping home-preserved food safe during storage.

Processing destroys the yeast, mold, and bacteria that can infect a jar after it's packed. Left untreated, these microorganisms spoil the contents and can cause illness. Proper processing creates an airtight vacuum seal between the lid and the jar, preventing microorganisms from entering during storage. High temperatures also destroy enzymes so fruits and vegetables retain their color, texture, and quality.

For fruits (which are naturally acidic) and acidic vegetables (such as most tomatoes), processing involves heating the packed jars in a boiling-water bath. This requires a large canning kettle filled with enough briskly boiling water to cover the jars by one to two inches. A lid covers the canner, while a removable rack keeps the jars from sitting directly on the bottom, holds them relatively steady during processing, and easier to lift from the water once processing is finished.

For foods with little natural acidity—such as corn, beans, meat, or fish—"pressure canning" is necessary in order to raise the boiling point above 212° F (100° C). This generates high enough temperatures to kill heat-resistant microorganisms and their spores. While pressure canning is more complicated, it's absolutely essential to keep low-acid foods safe.

There are lots of resources available! Beginning canners and seasoned preservers alike can look for up-to-date guides to home preserving in grocery stores, or check out sites such as Having current information is important!

Good luck and have fun. You'll enjoy the fruits of your labors come winter!

Anne & Sue




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