Food Preservation through Canning: Water Bath vs. Pressure

In a recent post, I discussed the basic science behind proper canning and the importance of testing your pressure canner dial gauge annually. This post, I will provide an overview of the two most common methods of food preservation, water bath and pressure canning. Understanding the difference in the two methods and knowing which to use for the product you are preserving will help safeguard those consuming the finished product. While I will not discuss detailed instructions for each process, as that is best done in person in a hands-on learning environment, this introductory information can help you prepare as you explore food preservation through canning.

Water bath canning uses boiling water (212° at sea-level). to preserve food. If you plan on processing acidic foods, such as fruits (jellies, jams, preserves, marmalades, and butters) tomatoes, pickles, and relishes, water bath is the recommended method. Microorganisms that cause acidic foods to spoil are destroyed by the heat produced from the boiling water.

Pressure canning uses pressure to process foods at a higher temperature (usually 240°) than water bath canning. If you plan on preserving low acidic foods, you want to use the pressure canning method. Examples of low acidic foods are vegetables, meats, poultry, and fish. Pressure canning will provide enough heat to kill bacteria that cause botulism and other types of spoilage. Although botulism is considered rare, it very serious and can be fatal. When using a pressure canner to preserve foods, it is important to read and follow the manufacturer’s instructions.

If canning in altitudes above 1000 feet, adjustments will need to be made as this changes the temperature at which water boils. Luckily, Rains and surrounding counties are far enough below 1000 feet to avoid this issue, but it is something to keep in mind if in another location. Additionally, each food has a specific processing time based on extensive research to determine food safety. Processing times must be followed exactly to avoid food safety and quality issues.

If you are interested in additional information on canning, please contact the Rains County Texas A&M AgriLife Extension office. If you like to do your own research, I recommend reviewing a copy of So Easy to Preserve (Andress & Harrison, 2020), a University of Georgia Extension publication. First released 1984, this publication is one of the most complete resources available on canning. In addition to step-by-step instructions, in-depth information, and problem solving, the 388-page book offers more than 185 recipes tested by highly trained Extension faculty.

As a reminder, it is important to test your dial gauge annually. The Rains County Texas A&M AgriLife Extension provides free dial gauge testing (for most dials). Please call (903) 473-4580 or email sarah.latham@ag.tamu.edu to set up a test time. Following your dial gauge test, you will receive written test results with instructions to adjust the pounds of pressure for proper cooking as well as information on replacement parts, if needed. Additionally, gaskets and plugs will be inspected. Overtime, rubber seals may become worn or brittle and need replacing. If needed, information on replacement parts will be provided.

In the meantime, if you have questions or concerns, please contact me, (903) 473-4580 or email Sarah.Latham@ag.tamu.edu. To view upcoming events or additional information please visit https://rains.agrilife.org/ or follow Rains County AgriLife on Facebook.

References:

Andress, E. & Harrison, J. (2020). So easy to preserve (6th Edition). University of Georgia Extension.

Food Preservation through Canning: Dial Gauge Testing

Canning is one of the easiest and most common methods of food preservation. Proper canning practices create a vacuum tight seal and preserve food by removing oxygen, destroying enzymes, and preventing growth of undesirable microorganisms, yeasts, and molds (National Center for Home Food Preservation, 2021). Canning has been in practice for centuries, but the USDA produced the first publication on home canning in 1909 (Andress & Kuhn, 1998). The two main types of canning include boiling-water (water bath) canners and pressure canners. Over the next few weeks, I will be discussing various aspects of food preservation through canning.

Over the past few years there has been an increased interest in backyard and community gardening across the country. Gardening attracts people for a variety of reasons; whether it be the security of growing your own food, the allure of consuming fresh fruits and vegetables, or the stress relief associated with working the soil, people are exploring gardening at an impressive rate. If you have ever grown a garden then you know it is not easy and if you are lucky enough to be rewarded with an abundance of your own produce, then you also understand the importance of food preservation.

Before getting into more specific topics, it is important to discuss dial gauge testing on your presser canner. As you handle and use your pressure canner the calibration of the dial gauge can become in accurate and should be tested each year before you begin the canning process. If your dial gauge is inaccurate (providing a lower or higher pressure reading), your food may not reach the proper temperature needed to kill harmful bacteria (lower pressure reading) or the temperature may get too high and overcook your food, resulting in quality and texture issues (higher pressure reading). Canning food at too low a pressure is a safety issue. If you have a pressure canner with a weighted gauge, you do not need to be check annually for accuracy as a weighted gauge does not get out of calibration.

The Rains County Texas A&M AgriLife Extension provides free dial gauge testing (for most dials). If you would like your pressure canner dial gauge tested, please call (903) 473-4580 or email sarah.latham@ag.tamu.edu to set up a test time. Following your dial gauge test, you will receive written test results with instructions to adjust the pounds of pressure for proper cooking as well as information on replacement parts, if needed.  Additionally, gaskets and plugs will be inspected. Overtime, rubber seals may become worn or brittle and need replacing. If needed, information on replacement parts will be provided.

Stay tuned for the next Food Preservation through Canning post discussing the difference between water bath and pressure canning methods.

In the meantime, if you have questions or concerns, please contact me, (903) 473-4580 or email Sarah.Latham@ag.tamu.edu. To view upcoming events or additional information please visit https://rains.agrilife.org/ or follow Rains CountyAgriLife on Facebook.

References:

National Center for Home Food Preservation. (2021) General Canning Information. https://nchfp.uga.edu/how/general.html

Andress, E. & Kuhn, G. (1998). Critical Review of Home Preservation Literature and Current Research. Athens, GA: University of Georgia, Cooperative Extension Service.