Why Mason-Type Canning Jars?
The major reason we suggest Mason-type canning containers is our experience with them and their reduced rate of breakage in contrast to mayonnaise jars, salad dressing containers, spaghetti sauce jars or other containers not intended for canning. Home food conservation experts have dealt with different kinds of canning containers and their experience is reflected in the following long quote from the National Center for Home Food Preservation.
"Food may be canned in glass jars or metal containers. Metal containers can be utilized just when. They require special sealing devices and are a lot more pricey than containers.
"Regular and wide-mouth Mason-type, threaded, home-canning jars with self-sealing lids are the best option. They are readily available in 1/2 pint, pint, 1 1/2 pint, quart, and 1/2 gallon sizes. The basic jar mouth opening has to do with 2-3/8 inches. Wide-mouth containers have openings of about 3 inches, making them more quickly filled and emptied. Half-gallon containers might be utilized for canning very acid juices. Regular-mouth decorator jelly containers are offered in 8 and 12 ounce sizes. With careful use and handling, Mason jars may be reused sometimes, needing only new covers each time. When jars and covers are utilized properly, container seals and vacuums are outstanding and jar damage is uncommon.
"Most industrial pint- and quart-size mayonnaise or salad dressing jars may be used with new two-piece lids for canning acid foods. Nevertheless, you need to expect more seal failures and container damage. These containers have a narrower sealing surface area and are tempered less than Mason containers, and may be weakened by repeated contact with metal spoons or knives used in dispensing mayonnaise or salad dressing. Relatively unimportant scratches in glass might trigger splitting and damage while processing containers in a canner. Mayonnaise-type jars are not suggested for use with foods to be processed in a pressure canner because of extreme container breakage. Other industrial jars with mouths that can not be sealed with two-piece canning covers are not suggested for use in canning any food in the house."
Another benefit of using canning containers is that they normally have a consistent shape and hold a consistent volume. Forming and volume affect the rate of heating of the food in a container. It takes longer to warm the coldest point of food to the preferred temperature in bigger volume containers than it does in smaller sized volume containers; it takes longer to warm every particle of food in a fat jar than in a tall skinny jar. Our recommended, science-based procedures were identified for food in basic canning jars. No science-based recommendations are available for canning in Weck brand name containers or other jars closed with glass covers, rubber gaskets and clamps.
Ball and Kerr are only two offered brand names of Mason-type canning jars. Other brands of canning containers include Atlas, Mainstays (WalMart) and Golden Harvest. All satisfy advised requirements; however, we have years and years of experience with jars from Ball and Kerr.
Clemson's packaging professionals were inquired about utilizing mayonnaise jars versus basic canning jars for canning foods. They commented that the sides (sidewalls) of mayonnaise containers are considerably thinner than the sides of canning jars which mayonnaise containers are not constructed to hold up against the duplicated heating and cooling inherent in canning. While glass mayo jars in previous years might have been constructed with much heavier sidewalls, nowadays they are rather thin since they are built to decrease shipping weight.
So based upon the info that I have, using canning containers instead of mayonnaise or other containers is not a lot a matter of food safety as it is of avoiding breakage, avoiding possible resulting burns due to sprinkling or spilling, and avoiding the resulting product loss. The chance for damage is much greater with non-standard jars such as mayonnaise containers.