Living Well Los Alamos: Tis The Season For Canning

Living Well Los Alamos
Los Alamos

Pressure Canner Care and Maintenance

Tis the season for canning! Whether you are planning to can homemade applesauce, salsa from garden tomatoes or apricots from your fruit trees, well maintained equipment is one key to successful food preservation. This is especially true of pressure canners. 

To begin, check any rubber gaskets for cracks. Rubber that has dried out, cracked or broken can result in a loose seal and not being able to reach the appropriate pressure. New gaskets can be purchased from the manufacturer or at our local hardware store. With metal-to-metal canners this is not a concern.

Check that all vents and parts are working properly. Tighten any loose handles if necessary. It is necessary to have the dial gauge checked annually for accuracy. Your local Cooperative Extension Service usually provides this service free of charge. If your gauge is off by more than two pounds they will recommend you replace it. Replacements can be ordered from the canning manufacturer.

Often old pressure canners can be obtained inexpensively from garage sales or handed down by family members. Before using the canner, be sure it has been inspected and the gauge tested. Models made before the 1970s were typically not fitted with a rubber safety plug. This plug is a safety mechanism which will open and allow pressure from inside the canner to be released in the event of plugged vents or over-pressurization.

Also check that the device is a pressure canner and not a pressure cooker. Pressure cookers are a great tool in the kitchen, but because you cannot monitor the internal pressure they are not safe to use for food preservation. A pressure canner should be large enough to hold at least four quart jars. Anything smaller should not be used for canning.

On a related safety note, it is vital to follow the processing time and pressure adjustments for your local altitude. Refer to specific recipes for recommendations. If using a dial gauge at high altitudes, the pressure in the canner must be increased by one pound of pressure for each 2,000 ft. above sea level. If using a weighted gauge, the 15 pound weight must be used at all altitudes above 1,000 ft. You do not need to add additional processing time if the pressure of the canner is adequately adjusted.


Pressure Required to Reach 240 °F


Pressure Required

Sea Level to 2,000 ft.

11 lb.

2,001 to 4,000 ft.

12 lb.

4,001 to 6,000 ft.

13 lb.

6,001 to 8,000 ft.

14 lb.

8,001 to 10,000 ft.

15 lb.

Source: USDA Food Safety and Inspection Service

When you are through with a canning project it is important to store your equipment properly. Begin by removing rubber gaskets and washing the canner in hot, soapy water and allow to dry. To clean the vent, draw a piece of clean string through the opening. If there are darkened areas inside the canner, fill the canner with a mixture of 1 Tablespoon cream of tartar for every quart of water until it reaches above the darkened area. Heat and boil, covered , until dark spot are no longer visible. Then wash, rinse and dry the canner and rack. Take care not to submerge the dial gauge if it is still attached. Store the canner with crumpled paper towels around the rack. This will help absorb moisture and odors. Store the lid upside down, not sealed to the canner.

Taking these steps will go a long way to ensure you have a safe and successful canning season. To have your canner inspected or gauge checked , or if you have questions about food preservation, contact the Los Alamos County Cooperative Extension Service.

Source of material: University of Georgia National Center for Home Food Preservation and USDA Complete Guide to Home Canning

Helen Idzorek is the extension home economist and 4-H agent for New Mexico State University Cooperative Extension Service. She can be reached at or at 505.662.2656. The Los Alamos County Cooperative Extension Service is temporarily located in the old Red Cross Building at 2150 Juniper St. in Los Alamos.

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