Canning Methods to Preserve your Harvest  

We’re heading into autumn, one of my favorite seasons. I love the crisp air, the changing fall colors in New England and the Pacific Northwest, and the generally cooler weather as we head into winter.

This is a good time of year to consider preserving some of the bounty harvested from your garden. Stock your pantry with preserved foods like salsas, vegetable relishes, fruit jams and jellies, pickled vegetables and fruits, soups, and much more. One of the most popular options is canning (actually not in cans but in sealed glass jars, so it might be better called jarring, but that means something else.)

Besides canning, there are a few other methods for preserving fruits and veggies—freezing, drying, and salting—but in this post, we’ll cover home canning.

What is Canning?

Canning safely preserves food for long periods of time by processing it at high temperatures in a vacuum sealed jar to remove oxygen. The process inactivates enzymes and destroys microorganisms that would otherwise contaminate the food.

Food Safety

There are two basic canning methods: the water bath and pressure canning method. The type of food you are preserving determines the canning method. The water bath is best for high-acid foods and, other than the jars, requires no special equipment. Low-acid alkaline foods must be preserved using the pressure canning method which requires a pressure canner (different from a pressure cooker.)

In their guide, ”Complete Guide to Home Canning,” The National Center for Food Preservation stresses that, to ensure food safety, proper canning practices should include:

1. Carefully selecting and washing fresh food
2. Peeling certain fresh foods
3. “Hot packing” many foods
4. Adding acids (lemon juice or vinegar) to some foods
5. Using acceptable jars and self-sealing lids
6. Processing jars in boiling water or a pressure canner for the correct period of time.

Water Bath Canning

This quicker lower-temperature canning process uses a boiling water bath. The food’s high acidity levels and the heat work together to preserve high acid and pickled or sugary high PH foods, such as:

Fruits and fruit juices
Sugar preserves (jams and jellies)
Tomatoes with added acid such as lemon juice or vinegar
Pickles, veggies, and relishes

In a large pot such as a stock pot with a rack on the bottom, immerse the filled canning jars in boiling water for the amount of time called for in the particular canning recipe. The National Center for Food Preservation is a good source for safe canning recipes. After removal from the bath, a vacuum seal forms as the jars cool.

Pressure Canning Method

Today’s pressure canners are lightweight with removable racks and are deep enough to hold one layer of quart or smaller jars and some deep enough to hold two layers of jars a pint or smaller. They include a vent pipe/steam vent, have an automatic vent cover lock, a dial or weighted pressure gauge, and safety fuse. They heat the canned food to a temperature hotter than boiling water. To ensure safety, The National Center for Food Preservation recommends using only canners with the Underwriter’s Laboratory (UL) approval.

To prevent the growth of botulism, all unpicked, low alkaline foods must be preserved using the pressure method. Botulism is generally killed in boiling water, however, the spores are not, so hotter temperatures are required to safely destroy them.

Ready to Begin Canning?

Always begin with good-quality fruits and vegetables preferably freshly picked from the garden at their peak of quality, usually within 6 to 12 hours after harvest. Carefully check all food for quality and freshness. Cut off the small diseased spots and discard any rotting or moldy food.

The Jars

Although food may be canned in metal containers, they are more expensive than jars, require special sealing equipment and may only be used once.

For quality and safety, use regular or wide-mouth threaded Mason-type home canning jars with self-sealing lids. These jars come in ½ pint, pint, 1½ pint, quart, and ½ gallon sizes. Make sure to sterilize empty jars for jams, jellies, and pickled products processed less than 10 minutes.

Please share your own canning recipes with us!

For more information on safety and safe canning recipes, consult The National Center for Home Food Preservation where you can download the USDA Complete Guide to Home Canning.

Photo Credit: flickr.com/photos/irisphotos

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About the Author:

Author, designer, speaker, and influencer Robin Plaskoff Horton, is Editor-in-Chief of Urban Gardens, the award-winning and Webby-nominated home and garden, sustainable living, and travel webzine. Mashable named Urban Gardens “One of the top 10 must-follow home and garden Twitter accounts” and Better Homes and Gardens Magazine named Urban Gardens one the top 10 garden blogs for 2015.