by Dr. Lori Verderame
To learn about bottles and their value, you have to know how they were made. Find out if your bottle was mouth blown by gaffers and mold boys in the 1700s to the early 1900s or if your bottle was produced with the aid of an automated machine introduced in 1903.
Mouth blown glass bottles were hand-made formed in a mold. Uniformity is not maintained in mouth blown bottles. They can be unusually thick, inconsistently colored, and deformed. Mouth blown bottles were typically made by a group of artisans. They could produce about 2 bottles per minute.
How is a mouth blown glass bottle made?
A glass blower put glass on the end of his blow pipe within a mold. He would blow into the pipe and expand the glass taking on the shape of the mold. A furnace worker would keep the furnace hot, a mold boy would remove the bottle from the mold and a snapper would break the fused glass bottle from the blow pipe and bring it to the annealing or cooling area.
Glass blowers were paid well and found it difficult to make glass under the glass house’s hot conditions.
By 1903, the Owen Automatic Bottle Machine changed the history of bottles. A decade later, the majority of glass bottles were made by machine. A single person could operate the machine and with the aid of the machine’s 12 rotating heads hosting 2 molds per head, glass bottles could be made using a two mold process and pressurized air at a production rate of 600 bottles per minute.
Most machine-made bottles had applied color labels like soda bottles and milk bottles. A machine made bottle was uniform and could result in bubbles. When trying to identify a machine made bottle, do not be fooled by the bubbles in the glass. It is possible for an early 20th Century machine made glass bottle to show bubbles in the glass.
Knowing how a glass bottle was made will help you to identify the bottle and date the piece. And you can also learn how to recognize the age of a bottle by learning about their shapes, sizes, etc.
Get an online appraisal of your glass bottle from Dr. Lori.