How to Determine the Age of an Old Fruit Jar
This is how to tell the age of your old fruit jar.
You cannot determine the age of your fruit jar just by looking at a picture of it. You have to actually hold and inspect it. The most important age indicator is the presence or absence of a pontil scar. The pontil scar is the ring of glass or the black and red iron-like indention mark on the base of a jar or bottle; this indicates that the glassblower once held the item over a pontil rod while the glass was still hot and while the neck or the lip was shaped by hand. American bottles with pontil scars predate 1855 or so.
Another indicator that is used to tell the age of a fruit jar is the presence of mold seams. The earliest bottles or jars were made using the freeblown method, meaning they were blown without the use of a mold; thus, they will not have any mold seams. Bottle and jar seams which stop short of the bottle lip signify that the bottle has been blown into a mold first then finished by hand by including a top or by tooling the lip into shape. Dating after about 1915, machine-made jars come with mold seams which extend from the bottom up and across the top of the bottle or jar.
You can also tell the age of the fruit jar by examining it thoroughly. If the base has a round ring in it and its lip is smooth, then it was probably machine-made sometime after the turn of the century but probably before the 1930s. If the fruit jar has a rough, large, and jagged ring around its base, then it was probably made between 1900 and 1930 during which time the Owens machine was still in popular use.
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