Canning Your Vegetables Safely

— Written By Katie Rangel and last updated by Dawn Stone


Many people are returning to home canning or joining the movement for the first time. Unfortunately, many are making a mistake that can be deadly. People are canning their green beans and other vegetables in boiling water bath canners or ovens instead of using pressure canners. This is a big mistake and can lead to serious illness or death. In the past couple of years, there have been many events of botulism poisoning from improperly processed home canned green beans and other vegetables.

Canning low-acid vegetables, meats, fish and poultry requires the use of a pressure canner. Spores of Clostridium botulinum bacteria, as found naturally in soils, are very, very heat resistant. Even hours in the boiling water canner will not kill them if they are inside your jars of beans. Left alive after canning, they will eventually germinate into actively growing bacterial cells that will produce a deadly human toxin when consumed. The bacteria must be killed during the canning process otherwise the canned goods cannot be safely stored on the shelf. The only canner that can get hot enough to kill the bacteria is a pressure canner.

Signs of spoilage of a jar might include cloudy, bubbling liquid or jars that pop open after initially sealing. These signs of spoilage seem obvious but jars of improperly canned vegetables and meats can also contain the deadly botulism toxin without showing signs of spoilage. This is why it is important to properly can the jars to begin with so you kill the bacteria from the get-go.

There are two types of pressure canners available: a dial gauge type and a weighted gauge type. Dial gauge canners use a dial to indicate or show the pressure inside the canner. It is necessary to have the dial gauge tested for accuracy before each canning season or after dropping it. You can call the Randolph County Cooperative Extension office at 336-318-6000 and make an appointment with me to check your dial gauge and make sure it is working properly. The gauge test is completely free and takes only about 5 minutes to conduct. After your gauge has been tested for accuracy, you can continue canning with confidence. You can also use a weighted gauge type canner. These types of canner do not need to be tested. There are several styles of weighted gauge canners in the marketplace. They have weights on the open vents that let you choose 5, 10 or 15 pounds pressure for processing.

You want to make sure you select a pressure canner/cooker that is capable of holding at least 4 quart size jars, on the rack, with the lid in place when you are ready to can. If it is smaller than that, we do not recommend it for home canning. Also make sure all parts of your pressure canner are in good condition. If your canner has a rubber gasket, make sure it is flexible and soft. You do not want your rubber gasket to be brittle, sticky or cracked. Also, check the openings on any small pipes or vent ports to be sure they are clean and clear of any debris. Altitude adjustments for processing are also very important for safety and should be with your manufacturer’s instructions. If you have any questions, you can always call your local cooperative extension office. Pressure canners should also have the air vented from them for 10 minutes of boiling before you pressurize the canner. You can get step-by step instructions for this from your local extension office or by visiting the National Center for Home Food Preservation’s website.

If your pressure canner has not yet been used this season or is new out of the box, it is a good idea to make sure it is working properly before preparing a canner load of jars. Put several inches of water in your pressure canner, and pressurize it as if canning. Make sure it gets to the pressure needed and can be maintained there without leaking. This is a good time to practice de-pressurizing the canner as if it had jars in it and then go through the steps for opening your canner as desired. As mentioned before, you can get step-by step instructions for using and caring for your pressure canner from your local cooperative extension office.

Using up-to-date canning instructions from a reliable source is essential. Scientific knowledge and equipment has changed since earlier generations and it is in your best interest to use the most up-to date information. If you have questions or concerns about canning, feel free to call me at the Randolph County Cooperative Extension Office (336-318-6000). Can Safely!