3 Things to Look For When Buying a Pressure Canner

When canning low-acid vegetables, meats and soups, they must be processed in a pressure canner in order to destroy botulism spores that can cause a deadly illness. These foods cannot be safely processed in a boiling water bath.

So, if you need to buy or replace a pressure canner, what features are you going to look for?

First, decide if you want a dial gauge or a weighted gauge.

The dial gauge adjusts pressure by small increments. You do need to keep an eye on the dial gauge while processing food to adjust the burner heat so that pressure does not go below the specified pressure, which would require you to start over the process time. Dial gauges need to be tested for accuracy each year before the canning season.

A weighted gauge indicates pressure when the weight jiggles. Weights usually indicate pressure at 5, 10, and 15 pounds. Some weights are a flat disk about one-half inch thick with three holes — one indicating 5; another, 10; and another, 15. A different type is a three-piece weight with a stem used by itself for 5 pounds, one disk added for 10 pounds, and two disks added for 15 pounds. There is also a pyramid-shaped weight that comes apart in three pieces. Check the pressure-canner manual to see how the weights are taken apart and how they are applied to the canner. Most weights are easy to use, but some designs can cause steam burns as you place them on the vent pipe. A weighted gauge indicates the pressure by “jiggling.” Again, you will need to check the manual to see if it jiggles so many times a minute or if it jiggles continuously while processing. An advantage of a weighted gauge is that you can hear when it is at the correct pressure and do not need to be in close proximity the entire time the food is processing.

The pressure for processing low-acid foods at or below 1,000 feet is 10 pounds for a weighted-gauge canner. (A 5-pound weight is used for high-acid foods.) At altitudes above 1,000 feet, the only choice is to use the 15-pound weight. It is not possible to make the incremental adjustments in pressure that can be made with a dial gauge. Weighted gauges do not go out of calibration and do not require yearly testing

Second, consider the seal. Most pressure canners seal with a rubber gasket that sits in a trough in the lid and slides into place on top of the canner, forming a seal. Gaskets should be replaced when they shrink or become brittle. Another type of canner seals metal to metal with the lid and canner beveled so that they come precisely together. This type of lid is held into place with six lugs. The All-American canner is the only canner with a metal to metal seal.

Many canners made today are lightweight aluminum and easy to handle. However, the All-American canner is made of heavyweight aluminum. The weight of the canner does not affect the safety of the food processed inside.

Third, consider the heating source. Most canners can be used on gas and electric burners. Manufacturers caution against using portable burners because of the danger of tipping over. Several manufacturers say not to use their canner on a smooth-top stove. In some cases, the weight of the canner may crack or otherwise damage the ceramic top. In other cases, the heating method of the stove may cycle on and off as it reaches a certain temperature. If this happens, it will cause the temperature inside the canner to fall and could cause the food to be under-processed and potentially unsafe. Induction burners require a magnetic metal to conduct heat to the pot. Several manufacturers have developed a pressure canner with a stainless-steel bottom that can be used on an induction burner.

Another choice is an electric digital pressure canner that works with sensors to automatically do each step in processing and even pre-heats the jars. It automatically adjusts for high altitude canning. It also can be used as a boiling water canner. However, it holds fewer jars — only 5 quart jars or 8 pint jars. It claims it meets USDA home canning guidelines, but USDA and the National Center for Home Food Preservation do not endorse any canner.

Electric multi-cookers are not suitable for canning.

Other features that all canners should have include a vent pipe, a pressure lock, and an over-pressure plug. They are most often located on the lid, but some models have the pressure lock and over-pressure venting in or under the handle.

If you have food preservation questions, a home economist is available to answer questions on Wednesdays, from 10 a.m. to 2 p.m., by calling 717-394-6851 or writing to Penn State Extension, Lancaster County, 1383 Arcadia Road, Room 140, Lancaster, PA 17601.

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