Article and audio introduction by Samantha Kennedy, Family and Consumer Sciences
Over the last several months, as you’ve learned to adjust to the restrictions of the COVID-19 pandemic, you may have become more interested in producing and preserving your own food. Home food preservation, more specifically canning, has grown in popularity in recent years, and if done correctly, can be a great way to stock up on healthy and delicious fruits, vegetables, and even meats that will last months in your pantry.
Water bath and pressure canning are the two most common methods of preserving foods in canning jars. Water bath canning is used for high-acid foods (pH of 4.6 or less) such as most fruits and tomatoes, and acidified foods, while pressure canning is used for low-acid foods (pH of more than 4.6) such as vegetables and meats.
However, another less common method of canning is steam canning. According to University of Wisconsin Extension researchers, steam canning involves processing naturally high-acid foods (e.g. peaches, pears, or apples), acidified foods (e.g. pickles and salsa), and/or jams and jellies in a pure steam environment that can maintain a temperature of 210-212 degrees F.
Just like with water bath and pressure canning, critical process parameters must be followed during steam canning as well. Only use approved, research-tested recipes from sources such as the USDA, the National Center for Home Food Preservation, and the Ball Blue Book. Only foods with processing times of 45 minutes or less, including modifications for elevation, should be steam canned. Do not rely on recipes found on the internet unless they come from one of the above sources. Even recipes found in the canner’s user manual may not be reliable, so please only use approved canning recipes to ensure a safe final product.
What type of canner or appliance can be used for steam canning? The only type of steam canner that has been tested for safety and temperature consistency is a dome-style steam canner. Shaped almost like an upside-down stock pot, it has a wide shallow base where the water and jars go and a tall top that fits over the jars and holds in the steam, maintaining the temperature between 210-212 degrees F.
What about an Instant Pot? (Note: Brand names are only used as examples and do not imply endorsement.) Newer models of these appliances – also known as multicookers or electric pressure cookers – have a built-in canning function and claim that they can be used for safe home canning. However, they have not been fully tested for safety in home food preservation and are NOT recommended for ANY type of canning.
Since the equipment – its structure, materials, and function – is different from traditional canners that have been tested for safety, it is not known whether the appropriate temperature can be adequately maintained during the canning process to ensure the elimination of foodborne pathogens such as Clostridium botulinum (the bacterium that causes botulism) and make sure the food is safe to eat. Therefore, it is recommended that only approved equipment be used for home canning.
The bottom line is: just because it’s on the internet doesn’t make it true. Always consult reliable sources for home canning information such as those listed above. Your local county Extension office is a great place to find reliable, research-based information on home canning and other topics. It is WAY better to be SAFE than SORRY.
Safe Preserving: Using a Steam Canner (University of Wisconsin Extension)
Burning Issues: Using Atmospheric Steam Canners (National Center for Home Food Preservation)
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