A Mason jar, also known as a canning jar, preserves jar or fruit jar, is a glass jar used in home canning to preserve food. It was named after American tinsmith John Landis Mason, who patented it in 1858. The jar's mouth has a screw thread on its outer perimeter to accept a metal ring, or band. The band, when screwed down, presses a separate stamped steel disc-shaped lid against the jar's rim. After Mason's patent expired, numerous other companies began manufacturing similar jars. Over the years, the brand name Mason became the genericized trademark for this style of glass home canning jar, and the word Mason can be seen on many Ball and Kerr brand jars. Such jars are occasionally referred to using common brand names such as in Ball jar (in the eastern US) and Kerr jar (in the western US), regardless of their actual brands. Glass canning jars provided a safe, reliable, and economical way to preserve all sorts of foodstuffs for later use and became an essential part of farming culture and home food storage, and preserved foods were displayed at county fairs for judging and awards. The peak use of Mason jars came during World War II, when the U.S. government rationed food, encouraging the public to grow their own. As migration to cities occurred, along with the rise of electrical refrigeration, the more efficient transport of goods made fruit and vegetables available year-round, reducing the need for home canning. On August 15, 2017, the registrar at National Day Calendar proclaimed National Mason Jar Day, to be observed annually as a national holiday on November 30, beginning in 2017.
History
Before Mason
French chef Nicolas Appert invented the method of preserving food by enclosing it in sealed containers. Among the earliest glass jars used for home canning were wax sealers, named in reference to the sealing wax that was poured into a channel around the lip to secure a tin lid. This process, though complicated and error-prone, became popular in the late 1830s or early 1840s and was still used to seal fruit jars until about 1890. The wax sealing process was largely the only one available until other sealing methods were developed.
John Landis Mason
In 1858, a Vineland, New Jersey tinsmith named John Landis Mason (1832–1902) invented and patented a screw-threaded glass jar or bottle that became known as the Mason jar (U.S. patent no. 22,186.) From when it was first patented Mason jars have had hundreds of variations in shape and cap design. After Mason's patent expired, many other manufacturers produced glass jars for home canning using the Mason-style jar.
The initial form of closure for the glass canning jar was a zinc screw-on cap, the precursor to today's screw-on lids. It usually had a milk-glass liner, but some of the earliest lids may have had transparent glass liners. The cap screwed down onto a rubber ring on the shoulder of the jar, not the lip. Between 1860 and 1900, many other patents were issued for Mason jar improvements and closures. In 1903 Alexander Kerr introduced lids with a permanent rubber seal. His improved design in 1915 used the modern design. Jars are closed with two-piece metal lids that seal on the rim. The jar lid has a rubber or rubber-like sealing surface and is held in place by a separate metal band. Mason sold the patents for the Mason jar to the Sheet Metal Screw Company of Lewis R. Boyd in 1859. Boyd had patented a white milk-glass insert for the zinc screw lids to theoretically lessen the chances that food would be tainted by contact with the metal lid. In 1871, Mason partnered with Boyd in the Consolidated Fruit Jar Company which licensed Mason jar patents to numerous glass makers. Letters of patent issued to Mason on May 10, 1870, for improvements to his fruit-canning jar was determined to be invalid as a result of a patent infringement case brought before the Southern District of New York on June 11, 1874. The court acknowledged that Mason invented the jar in 1859, but he did not apply for a patent for an improved version of the fruit jar until 1868. In the meantime, several others had patented designs and Mason had known these jars were being produced and sold. The court ruled that Mason's delay in protecting his patent indicated he had abandoned his invention in the intervening years between 1859 and 1868 and had forfeited his patent. The court's decision allowed other manufacturers to patent, produce, and sell glass jars for canning.
Design variations Variations of the Mason jar include the "improved Mason," which sealed on a shoulder above the thread instead of below, and the Atlas Strong Shoulder, with a reinforced shoulder area (as the original design was subject to cracks from the stress at the sealing point). A new type of Mason jar known as a "bead" jar was introduced c. 1910–1915. These continuous screw-thread jars were designed with a bead between the screw threads and the shoulder as a sealing surface. The Ball Corporation's "Perfect Mason" jar, one of the most common jars of this style, was introduced c. 1913 and produced until the mid-20th century. It had several variations, including a square-shaped jar.
Ball Corporation brands The Ball Corporation, which once dominated the market as the largest domestic manufacturer of home canning jars, spun off its home-canning business in 1993. In 1939 the company manufactured 54% of all the canning jars made in the US. Ball ceased production of canning jars when its subsidiary, Alltrista, became a separate company in 1993. Ball Corp. acquired certain Kerr assets, including factories, in 1992 and the Kerr brand of glass home canning jars was absorbed into Alltrista in 1996. Alltrista was renamed Jarden Corporation in 2002. Newell Brands acquired Jarden Corporation in 2016. As of 2022, Newell manufactures canning jars under the brand names Ball, Bernardin, Golden Harvest, and Kerr.
Contemporary jar design
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