I get many telephone calls at work from people asking me the question "Just how old is my bottle?" I will try to give some guidelines here to help people determine, just how old is their bottle.
I will start with the oldest bottles and work my way forward in time.
The oldest bottles are going to be bottles from grocers and druggist who sold bourbon and rye under their own label. These bottles were often hand blown glass and will have air bubbles in the glass as well as other imperfections such as a not quite straight neck. These bottles will date from the early 19th century up to about the 1880's. Labels will often be plain in design and simply read "Bourbon" or "Rye" but sometimes will include the name of the grocer who bottled the whiskey.
Towards the end of the 19th century there were improvemnets in industry that allowed machine made bottles. They will often have the air bubbles in the glass but will also show the joints where the mold pieces fit together forming seams in the glass. The earliest bottles were made with a three piece mold and the seems will run up the sides of the bottle but end where the neck is formed. After about 1890 a two piece mold process was developed and the seams run all the way up the sides of the bottle.
Before prohibition, the barrel was the most common packaging for the distiller. Jugs and Bar Decanters with the distiller's name or the brand name were often sold with a barrel of whiskey and those are still found today. These bar decanters were often cut leaded glass or crystal. Some of these decanters have even inspired bottles for the 20th century distillers. In the 1950's J W Dant had a "pinch" bottle based upon the old "pinch decanters" of the 19th century. Gentleman Jack and the Sazerac Rye bottles are also based upon these bar decanters. It is easy to tell the difference between the old and new. The older decanters are much heavier with crisper lines - facets are often on the verge of being sharp.
In 1897 the Bottled-in-Bond act pased and gave consumers a great tool for judging just how old their whiskey was in the bottle. It also helps to date the bottle. The government tax stamp was green with Carlisle's portrait over the cork. On the sides it had the date the whiskey was made and the date the whiskey was bottled.
For bottles that are empty, the label also can give a clue to age. In 1906 the Pure Food and Drug Act was passed. The label will often say "Pure Food Whiskey". There will also be warning about re-using the bottle. Label styles can also help with determining age. The fashions of the times will affect the design of the label and sometimes the glass bottle itself. A strong art deco design glass and label will be a post prohibition bottle from the 1930's.
After prohibition there was a strong influence from the U.S. government in the design of whiskey labeling. The back label of the bottle will often give the distillery information such as DSP# and location. This was common from the 1930's until de-regulation under Ronald regan took the teeth out of the bottled-in-bond act in 1982.
In 1979 and 1980 the distillery's switched to metric bottles and in those two yeaqrs the bottles will give fluid ounces and metric measurement. If it says 4/5 quart, then the bottle is older than 1979. If it has both styles it is 1979 or 1980. If it is in liters, then it is 1981 or newer. In the late 1980's the computer bar code starts to appear on labels. About 1989 or 1990 then the government required warning labels such as drinking is bad for the unborn children, so drink if you are pregnant.
I hope this will give you someplace to start when determining the age of your bottle. For information about the distiller or the brand, you can search the "bourbon lore" forum here for timelines of most major brands and distillers.
"Our people live almost exclusively on whiskey" - E H Taylor, Jr. 25 April 1873