Pressure cookers versus pressure canners
The difference between pressure cookers and pressure canners is essential to know before beginning to can.
What’s the difference?
Pressure cookers and pressure canners are not the same, and the difference is important to know for food safety. Pressure cookers are typically used for cooking roasts and other larger cuts of meat in a quick manner. While they come in a variety of sizes, most hold four quarts or less and are more like large saucepans. Pressure canners on the other hand, are meant for processing low acid foods, like vegetables, meat and fish, for storage in canning jars. They are often much larger, holding seven quart jars or up to 24 half-pint jars.
Why can’t I can in my pressure cooker?
The main issue with canning in a pressure cooker is their smaller size. One of the most important and underrecognized steps in the canning process is the heat-up and cool-down time inside the canner. Pressure cookers are one-half to one-third the size of standard pressure canners, causing the heat-up and cool-down times to be significantly shorter. This difference could lead to an under-processed product, leaving an opportunity for dangerous botulism spores to survive.
Another reason using a pressure cooker as a pressure canner is unsafe is that many of them do not have a mechanism to measure the amount of pressure being applied to the jars, or the devices are frequently inacurrate. It is important to know exactly what the pressure inside the canner is in order to process canned goods properly. If there is no gauge, or if it is inaccurate, there is no way to know for sure if your food has been processed long enough or with enough pressure to inactivate botulism spores.
Some manufacturers of smaller pressure cooking devices say that they can be used for pressure canning, but it is the consumer’s responsibility to check with manufacturers about processing recommendations for these devices. The same is true with tabletop electric pressure cooking devices because they have not been tested or approved by the USDA for pressure canning.
What steps should I take before pressure canning?
- Make sure your device can hold at least four U.S. quart-size jars, upright, with lids. Anything smaller will significantly affect the heat-up and cool-down time and therefore possibly underprocess food.
- Check to see if the device has an accurate way to measure pressure. It should range from zero to twenty-five pounds and can be a gauge or a weight. There should also be a way to calibrate the device for accuracy.
- Your pressure canners needs to have a venting procedure to remove air from inside the canner.
Pressure canning is a great way to preserve low acid foods, but it can be dangerous if not done properly. Using the right equipment for the job is a good first step to ensuring safe food. Also note that there is no safe way to convert pressure canning recommendations for use in devices other than standard 16-22 quart pressure canners. MSU Extension recommends using science-based procedures and recipes for all canning.