When it comes time to preserving food in jars, make sure you have done your homework on selecting a jar safe for canning.
Photo: Stephanie Ostrenga Sprague/MSU Extension.
Not all canning jars are the same, especially when preserving produce. According to the National Center for Home Food Preservation, make sure you are using a Mason-type jar because they are specifically designed for home canning. Other types of jars may break when exposed to the heat or pressure that is part of the canning process.
At the store, you will notice that canning jars come in various sizes, from half-pint jars to half-gallon jars. Pint and quart jars are the most commonly used sizes for canning although some foods like jams and jellies require smaller jars. If a recipe does not specify a processing time in one of these jars, process half-pint and 12-ounce jars for the same time as pints. Half-gallon canning jars are recommended only for very acidic juices like apple and grape juice. For other juices, contact the jar manufacturer for processing times.
Note: You can process your food product in a smaller jar than listed on the research-tested recipe, not in a larger jar, and the processing time will remain the same. For example, if a recipe calls for a pint jar, you can process it in a half pint and use the same processing time recommended for pints.
The underside of the can lid shows a reddish-brown sealing compound. Photo: Beth Waitrovich.
Jar size and food product recommendations
Half pint jars: Most often used for preserves, jams, jellies.
Pint jars: Can be used for fruit, vegetables, salsa, pickles, meat.
Quart jars: Can be used for fruit, vegetables, meat.
Half-gallon jars: Recommended only for canning very acidic juices, like apple or grape.
What about the lids?
The most common canning lid sold today is a two-piece, self-sealing lid. This type consists of a flat metal disc that has a sealing compound around the outer edge and a separate metal screw band. Once the lid seals the jar, it is no longer usable for further canning. Unless the band begins to rust, it can be used multiple times. One-piece lids are not recommended for the home canner because there is not yet enough research to determine if they allow enough air to escape and create a safe vacuum seal.
Other types of jars and recommended uses
Jar
Use for Canning?
Other Uses
Designer jar from an online retailer
No, the shape and size of a jar affects how heat penetrates the jar and the safety of the canning process. Jars other than the standard sizes and shapes of Mason-type jars have not been tested or manufactured for the heat and processing time needed for home canning.
Display or storage.
Vintage jars
No, older blue, purple, and green jars in various shapes are no longer recommended for home canning. They have had years of use and stress, possibly weakening the glass in places that could cause breakage during processing times.
Display or storage.
Secondhand jars
Caution: You have yet to learn how they were stored. If the glass is under stress, it could break while canning.
Question the seller to see if you can determine how the jars were used and stored, and examine the jars for nicks, cracks and chips.
If jars have not been stored well, use for display or storage instead of canning.
Commercial jars
No, most are not a true pint or quart-size jar and do not have the flat rim for a lid to seal tightly. They are often considered “one-time” use jars and have seams that make them weak for processing and can result in breakage, especially in a pressure canner.
Storage or recycle.
Jar cleaning and inspection
One use for extra jars and lids after canning is to store leftover dry goods like barley. Photo: Stephanie Ostrenga Sprague.
Wash empty jars in hot water before each use and rinse well by hand or wash in a dishwasher. Unrinsed detergents may cause unnatural flavors and colors, so the rinse step is important.
To remove scale or hard-water films, the National Center for Home Food Preservation recommends soaking jars for several hours in a solution containing one cup vinegar (5% acidity) and one gallon of water.
Before beginning any canning recipe, prepare jars and lids as directed by the manufacturer. For example, Ball recommends that lids no longer be pre-warmed before canning. Ball shared that their latex-based lids have been changed to a substance called plastisol, which does not require preheating. The manufacturer’s directions can be found on the packaging of new jars or the manufacturer’s website.
Food safety educators are often asked how long a Mason jar is suitable for use and it depends on how you treat them. In general, if jars are stored carefully at proper temperatures, not knocked together and kept clean, they will last you several canning seasons.
Additional tips to keep jars in good condition
Check jars for chips, nicks and cracks at the beginning of the canning season because they can lead to breakage in the canner.
Avoid sudden temperature changes. Do not put a hot jar on a cold surface or put raw packed jars into boiling water. Use a rack on the bottom of the canner to prevent jars from sitting directly on the bottom of the canner.
Do not use metal utensils when removing air bubbles from hot jars, this can damage or break the glass.
Michigan State University Extension recommends following research-based recipes to get the best results with your canning efforts. By taking a few steps and ensuring your jars are safe you will reduce the risk of breakage and have safe home preserved foods to enjoy.
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