The Bug Jar Schedule

Did You Know?

The ring holds the lid in place during the canning process, which creates a partial vacuum, sealing the lid until opened.

The lids are sold separately so that the jars and rings can be reused.Mason jars are made of soda-lime glass, and come in a variety of sizes including pint, quart, half-gallon, and cup sizes, as well as in wide-mouth and regular mouth shapes.The most common US brands of Mason jars are Ball and Kerr, both brand names now part of the Jarden corporation.In home canning, food is packed into the jar, and the steel lid is placed on top of the jar with the integral rubber seal resting on the rim of the jar.

While largely supplanted by other methods for commercial mass-production, they are still commonly used in home canning.In modern usage, the terms often refer specifically to jars featuring a two-piece cover: An inner, flat, metal or glass lid, covered by a screw-on ring.

The band is screwed loosely over the lid, which will allow air and steam to escape.

While these jars are still sold for storage, they are now rarely used for canning.The heyday for jars was probably 1860-1900, when an explosion of patents for various closures were issued, ranging from the effective to the absurd.

A "popped up" (flat or convex) lid may be a sign of microbial growth, including potential botulism, or seal failure.