Canning 101

By NTFR Staff

It seems to happen every summer. The garden suddenly produces more tomatoes, cucumbers and green beans than anyone could possibly eat, and before long someone asks, “Maybe I should learn to can?”

For many families, canning is a tradition passed down for generations. For others, it’s a new hobby that offers the satisfaction of stocking pantry shelves with homegrown food. Either way, getting started can feel overwhelming. Pressure canners, boiling water baths, jars, lids, processing times and safety recommendations are enough to make anyone wonder where to begin.

Home canning isn’t difficult once you understand the basics.

Canning preserves food in sealed jars by heating them to destroy microorganisms and create a vacuum seal. The USDA approves only two methods for home canning: boiling water bath canning and pressure canning. Which one you use depends entirely on what you’re preserving.

A boiling water bath is exactly what it sounds like. You submerge filled jars completely in boiling water and process them for a specific amount of time. Because boiling water only reaches 212 degrees Fahrenheit at sea level, this method is safe only for foods that are naturally high in acid or have enough added acid to prevent dangerous bacteria from growing.

That makes water bath canning a good fit for jams, jellies, fruit preserves, pickles, chutneys, fruit butters and many tomato products that have the proper amount of bottled lemon juice or citric acid added according to a tested recipe.

Pressure canning works differently. A sealed canner traps steam, and the temperature climbs well above the boiling point of water to about 240 degrees Fahrenheit. That higher temperature is necessary to destroy Clostridium botulinum spores, which can survive ordinary boiling and produce the toxin that causes botulism.

Because of that, you must pressure can low-acid foods such as green beans, corn, carrots, potatoes, meats, poultry, seafood and soups. A boiling water bath isn’t safe for these foods, no matter how long you boil the jars.

For most beginners, water bath canning is the easiest place to start. The equipment costs less, the process is simpler and recipes like strawberry jam or dill pickles are forgiving enough to build confidence. Many people who enjoy preserving fruit eventually buy a pressure canner once they want to put up vegetables or homemade stock.

Pressure canning doesn’t need to be intimidating, either. Modern pressure canners include multiple built-in safety features and are far different from the exploding canners in the old stories many people heard decades ago. Like any kitchen tool, they’re safe when used according to the manufacturer’s directions and with tested recipes.

Whichever method you choose, one rule never changes: always use recipes that have been scientifically tested. Family recipes may taste wonderful fresh, but they aren’t always safe for canning. Changing ingredient amounts, thickening soups with flour, adding extra vegetables or reducing vinegar can all affect the safety of the finished product. The USDA and the National Center for Home Food Preservation remain the gold standards for home canning recipes and processing recommendations.

Today’s recommendations may also differ from the ones your grandparents followed. Research has improved over the years, and food safety guidance has changed with it. Methods like open-kettle canning, oven canning and sealing jars by turning them upside down are no longer considered safe for shelf-stable foods.

If you’ve never canned before, you don’t have to preserve an entire garden your first weekend. Start with one recipe. Learn how to prepare the jars, measure headspace, remove air bubbles and process them correctly. Once you hear that satisfying “ping” as the lids seal, you’ll understand why so many people find canning rewarding.

Opening a jar of peaches in January or serving homemade salsa long after the tomatoes are gone is a special kind of reward. With a little knowledge, the right equipment and a commitment to tested recipes, anyone can preserve the harvest safely for months to come.