I started looking & digging  up old dump sites for bottles in my early teens. It opened my eyes to the past & how life was like 100 years + ago.My first bottle, I found was a 1907 dated Washington, D.C. beer. To be able to hold a piece of history in my hands after being buried for a century. The bottle bug bite & I was hooked. These bottles come in all shape, sizes, colors, molds & closures.  It has been a passion since then. My hope is to help new & old collectors dated the age of the bottle they may find. This is a simple guide & there is alway exceptions to the actural age of some bottles. Two thing come to mind, 1)some early glass factory did not change over to the newest way due the cost & 2) there is may reproductions for high ended bottle that are made today using old methods. With this said :

1) Freeblown bottle made into the 1860's. Bottles blown outside of a mold with a pontil scar( sharp glass on base of bottle) - note these type bottles are not embossed in the glass. Comes in all colors, aqua is the most common.

2) Handblown with pontil scar made between 1840's- 1860's. Bottle blown into a mold with a pontil scar( sharp glass on base of bottle or could be iron colored). Comes in all colors, aqua is the most common. Many are embossed in the glass or have a fancy shape.

3) Three molds made between 1809-1880's. Bottle has a sean that goes around the bottle in the mid section & two seans that shot up from it. These can be pontil & some are not. 

4) Bimold made between 1870's - 1910. Seans on bottles stop on neck, the closure was hand made. Comes in all colors, clear is the most common.

5) Machine made 1903 to present. Seans on side bottle run up into top of lip. Comes in all colors clear is the most common. Two types of machine make cork top & screw top.

     A) Cork Top Machine made 1903- 1920's

     B) Screw top Machine made 1903- to present.