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The Difference Between a Pressure Canner and a Boiling Water Bath

Updated: Oct 25, 2023

The two basic tools for home canning are the pressure canner and the boiling water bath. Both are necessary items in the home canner’s pantry. Knowing the differences between a pressure canner and a boiling water bath will help you to choose the right equipment for the best preservation of your recipes.

Pressure Canner

What is Pressure Canning?

Low-acidic foods like meat and vegetables must be processed in a pressure canner. In order to destroy all bacteria, their spores, and the toxins they produce, low-acidic foods must be heated to a temperature of 240°F and held there for the time specified by the recipe. Because the steam inside the canner is pressurized, its temperature exceeds the boiling point of water. At 10 pounds of pressure, using a weighted-gauge canner, the temperature will reach 240°F (at or below 1,000 feet above sea level), which is hot enough to destroy the bacterial spores that emit toxins. If you are located at an elevation greater than 1,000 feet above sea level, you must increase the processing temperature by adjusting the pounds of pressure used; the processing time remains the same.

There are more components to the pressure canner than the water bath due to the need to maintain and monitor the pressure level. Each pressure canner is a little bit different so it is a good idea to familiarize yourself with the model that you have. If you do not have the owner’s manual often companies offer an online version for reference.

Parts of a Pressure Canner

The basic parts of a pressure canner besides the pot and the lid are some kind of rack to keep the jars from resting directly on the heat of the bottom, a gasket or tightening knobs for sealing the lid to the pot, and pressure monitoring equipment. If you have a gasket, it should be checked regularly to be sure it will seal. If it does not seal, pressure will never be maintained. Most hardware stores offer new gaskets or they can be found online but be prepared with your model number because there are many different kinds available. There is an overpressure plug that should be changed at the same time that usually comes in the same package. If for some reason your pressure went up too high this would blow out and release the pressure quickly. (Probably breaking your jars in the process.)

The pressure gauge is how you monitor the level of pressure in your device. It should be checked occasionally for accuracy. Agricultural university extension offices often offer that service. The pressure indicator is another safety feature that you can use to assess if there is pressure in the unit. The vent allows steam to escape which creates a vacuum that helps seal the jars. The pressure regulator is the little weight that goes over the vent. It maintains the pressure up to 15 pounds of pressure and then it will begin to rock releasing some of the pressure.

Water Bath Canning

A boiling water bath uses heat over a certain amount of time to preserve and seal canned foods. It processes food at 212 degrees Fahrenheit, the temperature of boiling water. The boiling water bath can be used to process high-acid foods like fruits, jams, juices, and pickles.

The boiling water bath is a pretty simple piece of equipment. The parts of a boiling water bath are the pot, the lid, and the jar rack.

How to make adjustments based on altitude:

Barometric pressure is reduced at high altitudes, affecting the temperature at which water boils. This means boiling water and pressure canning methods must be adjusted to ensure safe processing. When using the pressure canning method of canning, additional pounds of pressure are required. The boiling water bath requires additional time.

The following altitude charts give the requirements.

Altitude Chart – Pressure Canning

Altitude Chart - Pressure Canning

Altitude Chart – Water Bath Canning

Altitude Chart - Water Bath Canning

If you are interested in an introduction to the pressure canner follow this link:

View helpful tutorials on our YouTube channel at this link:

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