Preserving your harvest or farmers’ market haul in a pressure canner has many benefits. Here’s how to (safely) use a pressure canner at home, as well as when you should use pressure canning instead of traditional water bath canning.
Canning is a cooking method that enables you to save (preserve) fresh vegetables and fruit to enjoy months later.
People can for many reasons:
- Maybe you’ve inherited your mother’s pressure canner and three shelves of glass canning jars?
- Perhaps you doubled the size of your vegetable garden this year?
- Did you increase your community-supported agriculture (CSA) share to include bulk purchases?
- Maybe you’ve decided it’s time to move beyond quick refrigerator jams and investigate pressure canning as a way to use that equipment and preserve the bounty?
The importance of pressure canning! From “Take Care of Pressure Canners”, USDA, 1945.
What to Love About Pressure Canning
- You can preserve a wide variety of homegrown or locally produced vegetables, poultry, meats, and even seafood.
- You can take advantage of good buys on bulk produce, meats, or chicken.
- You can stock your shelves with home-canned convenience foods: beans, lentils, chickpeas, chicken, chilis, soups, broths, and squash or pumpkin for pies.
- Your canned products will not spoil during extended power outages or a freezer malfunction.
- Modern glass canning jars will last many years if properly cared for, so by saving your jars for reuse, you will lighten your trash load.
- Bragging rights. There’s nothing quite like showing off those pantry shelves groaning with dozens, maybe hundreds, of jars of home-canned goodies.
Why Use a Pressure Canner?
Pressure canning is the safe way to preserve what we call “low-acid” foods to eliminate the harmful bacteria Clostridium botulinum—the cause of a potentially deadly illness, botulism. Low-acid foods include vegetables, chicken, meats, seafood, soups, and stews—all easy to preserve.
Many of our grandmas canned products a different way—by using a water bath canner in which jars sit covered with boiling water. This method is still fine for “high-acid” foods, including most tomato products, jams, jellies, and vinegar pickles, because the acids in these products prevent the growth of harmful bacteria in the sealed jars.
However, many of our great-grandmas also canned low-acid products like corn, beans, and chicken the water-bath way, letting the kettle boil away for 2 or 3 hours. But by the late 1920s, scientists had identified strains of the C. botulinum bacteria whose spores could survive hours of boiling. This is why low-acid foods are best when canned in a pressure cooker, where trapped steam increases the pressure inside the cooker and raises the temperature to 240°F for an established processing time, well above the boiling temperature of 212°F.
In summary, a boiling water canner can be used for acid and properly acidified foods, while a pressure canner is used for low-acid foods.
For more, take a look at the fascinating history of USDA home canning recommendations.
What Supplies Are Needed for Pressure Canning?
- You need a pressure canner (not a pressure cooker). A pressure canner may cost $200 to $500 or more, depending on size and quality.
Note: The U.S. Department of Agriculture recommends using caution when canning in electric pressure cookers or regular pressure cookers, and does not recommend canning in small pressure cookers or using cooking times that are meant for pressure canners.
- You need canning jars and lids: Quart-size jars cost around $1 each, and single-use lids are $3 to $4 a dozen. Here’s the latest information about canning lids. Should you try reusable lids? Best to wait. Research isn’t in yet. See also.
- You need accessories: ladle, wide-mouth canning funnel, jar lifter, lots of clean kitchen towels, and potholders. Also helpful: a digital timer and a magnetic lid-lifter.
- You need a traditional stove with coil heating units or a gas stove. A smooth-top stove may not be safe or practical. Check with your stove manufacturer.
- You need time. Preparation, processing, and cooling down a single cannerful (4 to 20 quarts) may take 3 to 4 hours or more. When you have a load of fresh vegetables, meat, or poultry that’s ready to process, you will need to can it immediately to preserve its flavor and nutritional value.
- You need countertops and cutting boards for preparing the food; setting up your clean, empty jars; and allowing a cannerful of finished products to cool overnight.
- You need shelf space for storing your canned food.
A Canner’s Caveat
I’ve canned for decades, enjoy it, and recommend it. It brings great pleasure, but it’s a knowledge-intensive practice. You can’t really learn on the fly; it’s not like making a batch of blackberry jam or freezing a big bag of green beans. Ideally, you should do your research and collect your supplies in the year before you actually begin.
The bottom line: You probably don’t want to invest in the equipment and time involved with low-acid canning unless you plan to process a lot of food each year.
Canning green beans. Beans in jars waiting to be placed in a pressure canner. Credit: www.caes.uga.edu/
Learn to Love Canning: More Information
Safe, successful canning requires comprehensive, easy-to-follow guidance, informed by the latest scientific research and updated as new research becomes available. Consider these your trusted resources and follow their recommendations and tested recipes to the letter:
- Start with the U.S. Department of Agriculture’s Home Canning Guides. Read Guide 1: Principles of Home Canning thoroughly. See the useful glossary beginning on page 33. Guide 4 and Guide 5 contain information and recipes for preserving low-acid vegetables, poultry, meats, and seafoods.
- The National Center for Home Food Preservation offers everything you need to know about canning low-acid foods. Each link expands to reveal a wealth of information.
- Cooperative Extension Service offices around the nation offer home-canning information in a variety of formats: guidebooks and fact sheets, telephone hotlines, how-to videos, and in-person classes. Check your closest Extension office to find what they offer near you. Some state Extension programs offer Master Food Preserver training for volunteers.
- The Ball Corporation website has a wonderful section on low-acid pressure canning, including a useful troubleshooting (problem-solving) chart.
- Booklets that you can order and then put on a kitchen shelf to consult while working include the USDA Complete Guide to Home Canning, the Ball Blue Book Guide to Preserving (37th edition), and the University of Georgia’s So Easy to Preserve (this one also comes in a video version).
9 Tips For Preparing Delicious Canned Foods
- Familiarize yourself with all the instructions that came with your pressure canner. If you do not have them, find the manufacturer’s instructions for that model online or contact the manufacturer for help.
- If your canner has a dial gauge, have it checked every year to ensure its accuracy. To find out where to get it tested, check your state or county’s Cooperative Extension website or call your local Extension office. Or contact your canner manufacturer directly.
- Plan to use new or relatively new Mason-style jars in sizes appropriate for your product. Save old-fashioned jars with wire bails and glass lids, ornamental glass storage jars, or recycled pickle and peanut butter jars for other things.
- Wash your jars in the dishwasher but process your canned goods only on a stovetop. It is absolutely not safe to can anything in a dishwasher, oven, or microwave.
- Do not alter the proportions of ingredients and do not add thickeners or other ingredients not specified in the tested recipe.
- Follow the instructions for filling the jars; leave just the right amount of headspace and resist the temptation to overfill to get that last little bit into the jar. The specified headspace allows room for the food inside to expand while heated and create a strong vacuum as the jar cools down.
- Abide by the recommended times for venting and cooling the canner. Waiting the full time is essential to ensure both the safety of your finished product and your physical safety (e.g., from steam burns).
- For best flavor and nutritional value, eat what you’ve put by within a year or so.
- Can only the foods that you know you and your family will eat and enjoy—and you will enjoy the experience from beginning to last bite!
Here’s more information about where to find safe pressure canning recipes!
Want to try other types of preserving? Check out our Pickling Tips and Recipes, as well as How to Can Tomatoes and How to Make Jam.
What’s your favorite food to can? Let us know in the comments below!