How to Identify the Age of an Old Bottle

Turn the bottle over and examine the base. A rough looking rounded area on the bottom means the bottle was probably made before the 1850s---when glass blowers still made bottles by hand individually. The pontil mark, as that rough area is known, was caused by the tool (called a punty rod) used to hold the bottle as the lip (opening) was being shaped. When the tool was removed it left a characteristic mark.

Look closely at the neck of the bottle. According to Digger Odell Publications', "Bottle Basics," "One of the most important clues to the age of a bottle is the style of the lip." If there is a seam at the base of the lip on the shoulder, the bottle is pre-1890, before which all bottle lips were applied to the bottle as a secondary step. Before 1870 most lips were distorted or crude, containing many irregularities. Faint concentric rings around the bottle lip indicate a bottle made since 1880 when it became a common practice to use a "lipping" tool to make the lip more uniform. Screw tops---crudely made at first---did not come into existence until the 1860s and had ground lips.

Examine the bottle for a seam, which would indicate the bottle was produced in a mold. Between 1855 and 1870 a device called a snap case allowed glass blowers to produce bottles without the use of the punty rod---this produced a characteristic seam that continued under the bottom of the bottle, dividing it into halves with a circular mark in the center bottom. The first fully molded bottle---including the lip---was made around 1892.

Check the bottle for uniformity. Machine-made bottles from fully automated processes were the norm from the early 1900s, so hand-finishing was no longer required and hand finish marks therefore disappeared. Bottles are smoother and more uniform from the 1920s, and are less likely to have raised labels after the 1930s.

Consider the color. Most early bottles (but not all) were clear or a faint aqua color. Darker bottles were known---particularly for poisons and chemicals or for more artistic and expensive uses---but everyday bottles tended to be colorless or light colored. Because they were the common colors of their day, they are considered of less value than darker or more obscure colors.