A Mason jar is a molded glass jar that is originally used in canning to preserve food. Other common names for the original Mason jar include Ball jars (after the Ball Corporation), fruit jars and simply glass canning jars. All Mason jars are not created equal.

Can Mason jars be used for canning?

Mason-type canning jars are best because these jars have been specially tempered to withstand the heat necessary in the home-canning process. These jars are not very resistant to temperature extremes; they break easily. Also, lids may not seal on these jars because their sealing edge is rounded rather than flat.