How to Identify Old Bottles & Jars

Collecting old bottles and jars can be an interesting and engaging hobby. Antique bottles command a high value, and collectors can make a profit while reselling antique bottles and jars. It is important to accurately identify the age of old bottles and jars, so that you will be confident that you are in possession of a genuine item. Old bottles and jars exhibit several identifying design features that you can use as a guide to ascertain their authenticity.

Observe the style of the lip and mold seams. Bottles and jars made prior to 1870 were hand-blown and had an applied lip. The bottles produced during this period had no mold seams, and the lips or mouth of the bottle had a crude appearance, with drip marks below the band. Bottles and jars produced between 1880 and 1900 used a lipping or pressing tool to apply the lips and prepare the object for closure. The lipping tool applied an additional glass band around the opening of the neck and the glass band was then twisted in place, with the support of two other pieces clamped on its outside. As a result, it produced faint concentric rings around the mouth and upper portion of the neck, which erased the mold seam on these bottles and jars.

Examine the color of the bottle or jar. Aqua shades of light green or blue were common for bottles and jars produced before 1900. Amber or brown-colored glass, various shades of green -- including emerald, teal, blue-green and olive -- were other colors for bottles and jars made during this period. Some of these bottles were molded with ribbed patterns or figures, as well as the product and manufacturer name. Clear or colorless glass became widely available only after 1910, with the introduction of automatic bottle machines.

Turn the bottle on its base to look for the 'pontil' mark that was formed during the finishing process. Bottles and jars that were hand-blown before 1865 have a pontil mark, which is a rough spot that can vary in shape and appearance. A punty rod, which is an approximately six-foot long iron rod, was securely fixed to the base of the newly blown bottle, to hold it while applying the lip. Upon completion, the punty was then separated from the hot bottle, leaving behind the telltale scar as evidence.

Check for any embossing on the bottle or jar. Alcohol bottles produced between 1933 and 1970 have the words, “Federal Law Prohibits Sale or Reuse of this Bottle” embossed on them. Some bottles and jars produced from the late nineteenth century have numbers and letters embossed on them to indicate their patent dates, the product, manufacturer or other relevant information.