Many Ball mason jars have a number printed on the bottom of the jar, but this is a mold number that does not indicate the year of production. Rather, the mold number tells you where the jar was positioned on the glass-making machine that was used to produce it.

Why are Mason jars in short supply?

Though the mighty mason jar hasnt fallen from its throne online on sites like Pinterest and Instagram, the major jar and canning supply demand is due to the covid 19 pandemic of last year.