Canning season is quickly approaching, so it is a good time to review the fundamentals of canning jars and lids, including selecting the right products and using them properly.
Canning lids
Last year, the pandemic caused supply chain issues resulting in a shortage of canning lids. This shortage resulted in price gouging and the sale of counterfeit canning lids through various websites. Although production of lids manufactured by reputable brands has increased, there still is a risk of counterfeit products being sold. These counterfeit products often result in lid failures, such as improper sealing or buckling, which jeopardizes the safety of the canned food. When purchasing canning lids, make sure you are buying genuine products through reputable outlets. Many brands, such as Ball and Kerr, have a list of authorized retailers on their website. To ensure you are buying a genuine product, only buy lids from these authorized retailers.
The National Center for Home Food Preservation has the following recommendations for purchase and use of canning lids. Two-piece, metal, self-sealing canning lids are recommended. The lids consist of a flat metal lid containing a sealing material and a metal screw band. Although canning lids may be used up to 5 years from the date of manufacture, it is recommended to only buy enough lids you plan to use for the year. Canning lids are only designed to be used once, but the metal screw bands can be reused, provided that they are in good condition and do not contain rust.
Prior to using the lids, inspect each lid to ensure it is not old, dented, deformed or contains any defects in the sealing gasket. Be sure to follow the manufacturer’s directions for proper preparation of the lids. Many brands no longer require preheating of the lids prior to use, and boiling of the lids may result in seal failures. Before placing lids on filled jars, be sure to clean the jar rim to make sure there are no food particles on the rim which can interfere with proper sealing. Once the lid has been placed, the screw band should be applied to the jar and tightened per manufacturer’s instructions. If the screw bands are too loose, liquid and food may escape which can result in lid failures. Overtightening of the screw bands may result in the buckling of lids or breakage of jars. Never invert the jars as this may cause food or liquid to seep onto the seal which can result in a seal failure and unsafe food. Once the food has been properly processed, the lids have sealed and the jars are cooled, the screw band can be removed, washed, and re-used.
Canning jars
It is highly recommended to only use Mason-type regular or wide-mouth home-canning jars which can be used with the self-sealing two-piece lids. Mason canning jars are made with heat-tempered glass to withstand the heat during the canning process. These jars come in a variety of sizes. Always check your canning recipes before purchasing jars to ensure you will have the correct jar on hand. The processing times in the recipes are dependent on many factors including the size and shape of the jar. Given this, you cannot use a different size canning jar that is not specified in the recipe (for example, using quart jars in place of pint jars), as this could result in under processing of the food, and the potential for growth of disease-causing microorganisms. Additionally, using nonstandard shaped jars may also affect proper processing, thus resulting in unsafe canned food.
Always inspect jars for cracks, chips, or nicks as flaws in the jar may result in the lids not sealing, or cause jars to break during processing. Jars should be washed in hot soapy water and rinsed well, or washed in the dishwasher prior to use. After washing, submerge jars in a pot of simmering water (180 degrees Fahrenheit) until you are ready to fill them with food. If the recipe calls for a processing time of less than 10 minutes, the jars will need to be sterilized prior to use. This can be accomplished by submerging the jars in boiling water for 10 minutes. You will need to add an additional one minute of boiling for every 1,000 feet of elevation depending on your location. Keep the jars submerged until you are ready to fill them with food. Mason jars may be reused many times, but you will need to use a new lid.
For additional assistance with the selection and use of canning jars and lids, please contact your local Extension office. As a reminder, only use recipes from safe and researched backed resources. Your local Extension office can assist in providing you with recipes that will ensure your canned food is safe.
Smith is an assistant professor and statewide consumer food specialist for Washington State University. She can be reached at food.safety@wsu.edu. If you have a food safety question you would like to see appear in this column, send your question to us at food.safety@wsu.edu.
