There are three keys to help with dating most bottles: Side seams: None: bottle may be free blown, in which case it has a very uneven shape and dates before 1860. Or the bottle may have a nice even shape, but was spun in the mold to smooth out the seams; a practice common around 1900-1920.

How do you tell the age of an old bottle?

The embossed makers mark or letters on the side of a bottle or on the base of a bottle will help to reveal a bottles age. Marks or letters on collectible milk bottles and Coca Cola bottles are commonly indicators of age and origin.

How old are bottles with seams?

Dating Bottles with the The concept is that the higher the side mold seam on the bottle the later it was made - at least in the era from the early to mid 19th century until the first few decades of the 20th century.