Dating ball fruit jars
A band is screwed loosely over the lid, allowing air and steam to escape.The jar is heat sterilized in boiling water or steam and the lid is secured.Lightning fruit jars, another type of Mason jar, were not as common as the screw-thread version, but they were popular for home canning in the late nineteenth (19th) and early twentieth (20th) centuries. They are also produced in a variety of volumes, including cup (half-pint), pint, quart, and half-gallon. Jarden Corporation, based in Boca Raton, Florida, In home canning, food is packed into the mason jar, leaving some empty "head space" between the level of food and the top of the jar.The lid is placed on top of the jar with the integral rubber seal resting on the rim.The stopper or lid was typically made from metal, porcelain, or ceramic, while a rubber gasket was used to seal the container. The sealing surface on the jar was a "shelf" that supported the lower edge of the lid.Putnam modified de Quillfeldt's design so that the lid was secured by centering the wire bail between two raised dots or in a groove along the lid's center. A rubber gasket between the shelf and the bottom surface of the lid formed a secure seal when the wire closure was tightened.
An integral rubber ring on the underside of the lid creates a hermetic seal.The jar is then allowed to cool to room temperature.The cooling of the contents creates a vacuum in the head space, pulling the lid into tight contact with the jar rim to create a hermetic seal.Largely supplanted by other products and methods for commercial canning, such as tin cans and plastic containers, glass jars and metal lids are still commonly used in home canning.Mason jars are also called Ball jars, in reference to the Ball Corporation, an early and prolific manufacturer of glass canning jars; fruit jars for a common content; and glass canning jars a generic term reflecting their material and purpose. brands of Mason jars are Ball, Kerr, and Golden Harvest.