Testing Your Canner

There are two basic canning methods - water bath canning and pressure canning. Before starting the canning season, check to make sure your equipment is safe and ready to use.

Pressure Canners:

  • If your pressure canner has a dial gauge, have it checked once a year before the canning season. Also check it during the season if you use the canner frequently. Your local  Extension Service office can check the dial gauge on pressure canners.
  • If you cannot get it tested nearby, write to see if the manufacturer can do it. The manufacturer's name and address will be pressed into the canner or on a plate attached to it. Ask for shipping instructions. Pack it like fine crystal and label the package "fragile." If you do not have an instruction book for your canner, write for one.
  • If the gauge reading is off one pound or more, buy a new pressure gauge. If it is off less than one pound, tie a tag on the canner to remind yourself of the difference and adjust to pressure reading to allow for difference.
  • The weighted pressure control on canners does not need to be checked. Keep it clean and rust free.
  • In most canners there is a gasket. These gaskets are made of rubber or rubber-like compounds to keep steam from leaking out around the cover. You can remove and replace most gaskets as needed. Some only need to be turned to ensure a tight seal. Replace a worn, stretched or hardened gasket with a new one. Refer to the canner instructions for directions. Leakage makes it difficult to reach the right pressure and may cause the canner to boil dry.
  • Test your pressure canner before use taking a complete practice run with jars filled with water. This extra step may help to avoid mistakes later with your valuable produce.

Water Bath Canners:

  • These canners are made of aluminum or porcelain-covered steel. They have removable perforated racks or wire baskets and fitted lids. The canner must be deep enough so that at least 1 inch of briskly boiling water will be over the tops of jars during processing.
  • Enameled canner care: To prevent deposits from forming on your enameled canner, add several tablespoons of distilled vinegar into the water before you start processing.
  • Some boiling-water canners do not have flat bottoms. A flat bottom must be used on an electric range. Either a flat or ridged bottom can be used on a gas burner. To ensure uniform processing of all jars with an electric range, the canner should be no more than 4 inches wider in diameter than the element on which it is heated.

Steps for Successful Boiling-water Canning
1. Fill the canner halfway with water.
2. Preheat water to 140 degrees F. for raw-packed foods and to 180 degrees F. (simmering with steam) for hot-packed foods. Raw- or cold-packed foods are placed directly into hot jars and covered with hot syrup; hot-packed foods are partially cooked or heated through and placed hot into hot jars, and covered with hot syrup. See tested recipes for detailed instructions for various types of produce.
3. Load filled jars, fitted with lids, into the canner rack and use the handles to lower the rack into the water; or fill the canner, one jar at a time, with a jar lifter.
4. Add more boiling water, if needed, so the water level is at least 1 inch above jar tops.
5. Cover with the canner lid and turn heat to its highest position until water boils vigorously.
6. Set a timer for the number of minutes required for processing the food. (Check tested recipes for specific instructions for jams/jellies and pickles.)
7. Lower the heat setting to maintain a gentle boil throughout the process schedule.
8. Add more boiling water, if needed, to keep the water level to above one inch of the jar lids.
9. When jars have been boiled for the recommended time, turn off the heat and remove the canner lid.
10. Using a jar lifter, remove the jars and place them on a protected surface, leaving at least 1-inch spaces between the jars during cooling. Keep away from air drafts and let the jars cool at room temperature.