Home canning is a science, accuracy is crucial for safety

In southwest Missouri, food preservation is a time honored tradition for many families. However, if part of that tradition includes using old family recipes, it is wise to update to new recipes and methods according to Jennifer Nevatt, county engagement specialist in nutrition and health with University of Missouri Extension.

“Food preservation is a science and new research has led to new recommendations in the name of safety,” said Nevatt.

Here are answers to some of the most common food preservation questions asked of Nevatt in the last several months.

How often should I check my dial gauge? A pressure canner with a dial gauge should be tested and inspected annually before the start of each canning season. Even new canners fresh out of the box can have inaccurate dial gauges. MU Extension offices statewide are able to test pressure canners for accuracy. “Pressure canners with weighted gauges do not become uncalibrated and do not need to be checked for accuracy,” said Nevatt.

Can I use my pressure cooker to can foods? There is a difference between a pressure canner and a pressure cooker. Using pressure cookers is not recommended. If the cooker does not have the capacity to hold at least four quart jars it does not have the structural capability to pressure process low-acid foods safely and the risk of botulism is very high. “Instant pots should never be used for canning, even if the manufacturer states that it is an option,” said Nevatt.

What’s wrong with oven canning? Oven canning is extremely hazardous for a couple reasons. Product temperatures never exceed the boiling point so this process fails to destroy the spores of Clostridium botulinum and can cause the food to become toxic during storage. Canning jars are not designed for intense dry heat and may explode, resulting in serious cuts or burns.

My family always boiled lids, do we still need to? Most folks know to always use a new lid (flat) but there is no longer a need to boil lids. In late 2017, the Ball Corporation released newly formulated lids, “Sure Tight” lids, which only require washing before use. Heating up the lids before putting them on jars could actually lead to seal failures. If using an existing stock of older lids, follow the directions on the package.

Where can I learn more? MU Extension has an online Home Food Preservation course which is now available for $30 any time through Dec. 31. Nevatt can offer face to face workshops for $20/person on subjects such as pressure canning, steam canning, jams and jellies, salsa making, and pickling as classes fill. Space is limited and partner agencies are needed to host such classes. If you have canning questions, are interested in a class or in partnering, please contact my office at 417-357-6812 or check out the MU Extension website, https://extension2.missouri.edu/.

For more information, tested recipes, and related events, see MU Extension online