Some of us were lucky to learn food preservation skills at home, on long, hot summer days that now exist as fond memories. Many of us weren’t so lucky. Pressure canning in particular is a source of anxiety for new food preservers. The equipment may seem foreign, and if you aren’t careful, you can end up with food that’s unsafe to eat. Do respect food safety guidelines, but do not fear the useful technology that is pressure canning.
The Two Main Types of Canning
The easiest way to can foods — and the best place to start — is with simple water bath canning. With this method, jars are processed at the boiling point — 212 degrees Fahrenheit at sea level — which is hot enough to kill molds, yeasts and harmful bacteria, and to deactivate enzymes that lead to food spoilage. The boiling point is as high as you need to go to can foods that contain enough acid to prevent further microbial growth. These high-acid foods (pH 4.6 or lower) include most fruits, as well as some other foods to which acid has been added. Jams, jellies and vinegar pickles are good foods for beginners to can. Go to our canning resources page
If you really want to save money and become more self-sufficient, eventually you’ll graduate to pressure canning. With a pressure canner, you can preserve all kinds of low-acid foods (pH higher than 4.6), from green beans, venison and tuna to chicken soup, chili and spaghetti sauce. Two readers reported that they even employ the pressure canner to put up chicken feet and homemade dog food.
A pressure canner raises water beyond the boiling point, which allows food to reach temperatures as high as 240 degrees. That temperature kills certain bacteria, including Clostridium botulinum, which causes botulism food poisoning.
The Centers for Disease Control and Prevention has been tracking cases of botulism since 1973. The 2011 report cited only two canning-related cases of botulism — with no deaths — so the risk of this type of food poisoning is probably lower than you think. If you learn the basics and use tested pressure-canning recipes, you’ll relax and instead be able to focus on enjoying great foods.
The Benefits of Pressure Canning
Many of the benefits of canning are the same regardless of method. You’ll save money on groceries. You can store foods without relying on electricity or monopolizing freezer space. You’ll save time every day by shopping your own pantry. A few days spent canning can provide quick, heat-and-eat meals — the original fast food. Canning may seem a big time investment, but it’s concentrated time that results in time saved later. MOTHER EARTH NEWS reader Katrina Lee says she devotes one weekend per month to food preservation, and that’s enough to keep her family well-stocked with healthy food year-round.
You’ll save the most money if you preserve food you grow yourself. The savings can be considerable with food you buy, too, if you buy items in bulk when they are in season and abundant. For many canned goods, you don’t need to start with the best-looking ingredients. Ask for cheaper, less-than-perfect “seconds” at farmers markets. Your family will never know you cut some bad spots off that big pile of ripe veggies last August when they’re relishing your home-canned stew in January.
Pressure canning offers additional benefits beyond those you get with water bath canning. For example, you can extend the grocery savings to other kinds of foods (see “Which Method Do I Use?”). Reader Shelly Kave saves money by pressure-canning stocks from all of the scrap bones that would otherwise get thrown out. “It’s easy to put it on while doing other things around the kitchen,” she says. “And it really doesn’t take as long as you might think.”
Pressure canning allows you to make use of inexpensive cuts of meats that benefit from the tenderizing that high heat and prolonged cooking provides. As with produce, some meats are more available — and thus more affordable — in certain seasons. Spring is a good time to find farmers market deals on free-range chicken and lamb, while fall is the best time to stock up on beef, pork, venison and fish.
Know Your Pressure Canning Equipment
There are two types of pressure canners. Weighted-gauge models show pressure in units of 5, 10 and 15 pounds per square inch (psi). Dial gauges show a range from 5 to 15 psi, which is useful if you live at a high altitude. (Pressure adjustments must be made in small increments at altitudes above 1,000 feet.) Since the 1970s, canners have been manufactured with standard safety features. You may be able to find good deals on used pressure canners on websites such as Craigslist.org. The National Center for Home Food Preservation recommends purchasing a model that displays the Underwriter’s Laboratory (UL) approval. Be sure to check gaskets for cracks if you’re considering a used canner. Parts for most models are available online.
New pressure canners range from about $70 to several hundred dollars, depending on how well-made they are and the number of jars they hold. Some models have rubber gaskets that need to be replaced if they become cracked or stretched. Well-made models will last many years. All American Canners, the only company manufacturing pressure canners in the United States, makes models that have easy-to-read dial gauges and metal-to-metal locking that eliminates the need for replacement gaskets. Its most popular model (See Image Gallery) will process 19 pints (7 quarts) at one time and retails for about $200. Always read the owner’s manual, as different brands have different features.
Have your canner’s gauge checked for accuracy at the beginning of each canning season. Contact a hardware store or your local county extension agency for this service. Before each canning session, make sure the canner lid locks securely, the rubber gasket (if there is one) is not warped or cracked, and the valves are clear of debris. Pull a string or pipe cleaner through the small holes to clean them.
Which Method Do I Use?
Water Bath Canning
(pH 4.6 or lower)
Jams and jellies
(pH higher than 4.6)
Meat and seafood
Sauces, soups and stews
* Because they have varying acidities, tomatoes are at the edge of pH acceptability for water bath canning. To ensure safe water bath canning, Carol W. Costenbader, author of The Big Book of Preserving the Harvest, recommends adding 2 tablespoons of bottled lemon juice or half a teaspoon of citric acid per quart of whole, crushed or juiced tomatoes.
How to Use a Pressure Canner
Tested canning recipes will contain all of the information you need. Always read the entire recipe before beginning. Many of the steps for pressure canning are the same as those for water bath canning. Each year, check that your canner is in good working condition by taking it to your local extension office.
Pressure Canning Equipment
Canning jars with rings and new lids (wide-mouth jars are easiest to fill)
Pots, bowls, measuring cups and spoons
Plastic knife or wooden chopstick for removing air bubbles (metal knives can scratch glass jars)
Assemble Equipment and Ingredients: Though many sources will tell you to sterilize everything, this step is unnecessary. Pressure canning will kill all potential pathogens. Just start with clean equipment and a clean work surface. Discard any jars with nicks in the glass.
Prepare Recipe: Some recipes require you to pack raw food into the jars and then pour hot liquid over the food. With others, you’ll cook the food and then pack it hot.
Fill Jars: Be sure to leave the proper amount of headspace (the amount of space between the top of the food and the jar’s lid). Recipes should indicate how much headspace is necessary.
Seal Jars: Remove air bubbles by stirring with a knife or chopstick. Wipe the jar’s rim clean (a bit of vinegar on a cloth can cut through grease), set the lid on the rim, and twist on the ring just until it resists. Don’t over-tighten.
Prepare the Canner: Place jars on a rack in the canner and add 2 to 3 inches of water, unless otherwise specified. Secure the canner lid into its locked position. If using a weighted gauge, remove the weight. If using a dial gauge, open the petcock. Heat the canner over high heat until steam escapes. Allow steam to vent for 10 minutes. Attach the weight or close the petcock. Bring the canner to your recipe’s recommended pressure using the high heat setting.
Set a Timer: Begin timing when the weighted gauge is jiggling steadily (about 2 to 3 times per minute) or when the dial gauge displays the recipe’s recommended pressure. Be vigilant, and adjust the heat often to maintain the lowest heat under the canner that will keep the appropriate pressure. Remove the canner from the heat after the required time has elapsed.
Let the Canner Cool: Leave the canner alone until the pressure has released naturally, about 30 minutes for pints and 45 minutes for quarts. Some models have a feature that will alert you when the pressure is normal.
Remove the Weight or Open the Petcock: Let the canner sit undisturbed for a few minutes, then remove the lid. Lean back to avoid a steam burn. Let the open canner stand for 10 minutes.
Let the Jars Cool: Place a towel on the counter. Using a jar lifter, remove the jars to the towel, keeping them an inch apart to allow for air circulation. Let the jars cool for 12 to 24 hours, and then check the seals. The lids should not have any give when you press firmly on the center. If any jars didn’t seal, process them a second time.
Fill Your Pantry: Be sure to label jars with the date and contents. Remove the metal rings, as they can corrode during storage. Rings can be reused, but lids should not be.
Eat Up! For best quality, consume within 12 months.
Mother Earth News Home-Canning Guide: Find more in-depth instructions for water bath and pressure canning, tested recipes, favorite books, websites, and canning products — and even some canning-inspired artwork — on our comprehensive canning page.
The Big Book of Preserving the Harvest by Carol W. Costenbader
Preserving Summer’s Bounty by Rodale Food Center and Susan McClure
Ball Complete Book of Home Preserving by Judi Kingry and Lauren Devine