How to Date Kerr Mason Jars
Kerr Mason Jars, with their iconic design and timeless appeal, have been a staple in American households for over a century. These jars, known for their durability and airtight seal, have been used for canning, storage, and display. If you’re a collector or simply curious about the history behind these jars, learning how to date them can be a fascinating endeavor. In this article, we’ll explore the various methods and tips to help you determine the age of your Kerr Mason Jars.
Understanding the Basics
To begin dating Kerr Mason Jars, it’s essential to familiarize yourself with the basic components and markings. Kerr Glass Manufacturing Company, founded in 1905, produced these jars in various sizes, shapes, and designs. The jars typically feature a glass lid with a rubber seal and a metal band that secures the lid in place. The markings on the jar can provide valuable information about its age and origin.
Identifying the Manufacturer
The first step in dating a Kerr Mason Jar is to identify the manufacturer. Look for the following markings:
– “Kerr” or “Kerr Co.” embossed on the jar or lid.
– The date code, which is usually a combination of letters and numbers.
– The jar’s shape and size, which can help narrow down the year of production.
Understanding the Date Code
Kerr Glass Manufacturing Company used a date code system to indicate the year of production. The date code is typically found on the jar’s base or the inside of the lid. Here’s how to decode it:
– Look for a letter followed by a number. The letter represents the year, while the number indicates the month of production.
– For example, “A1” would mean the jar was produced in January 1915.
– Keep in mind that the date code system was used from 1915 to 1964. After that, Kerr switched to a new numbering system.
Examining the Design and Shape
The design and shape of a Kerr Mason Jar can also provide clues about its age. Here are some key features to look for:
– Early jars (1905-1920) often feature a rounded bottom and a smooth, unembossed design.
– From 1920 to 1940, the jars had a straight-sided design with a flat bottom.
– In the 1940s, Kerr introduced the “Ball Jar” design, which features a ribbed top and a flat bottom.
– The company continued to modify the design over the years, so it’s essential to compare your jar with known examples.
Using Resources
To help you date your Kerr Mason Jars, there are several resources available:
– Online forums and communities dedicated to jar collecting, such as the National Association of Mason Jar Collectors.
– Books and websites that provide detailed information on Kerr Mason Jars, including their history and production years.
– Online databases and auction sites that list jars by date and manufacturer.
Conclusion
Dating Kerr Mason Jars can be a rewarding and educational experience. By understanding the basics, identifying the manufacturer, decoding the date code, examining the design and shape, and utilizing available resources, you can determine the age of your jars with confidence. Whether you’re a collector or simply appreciate the history behind these classic jars, the process of dating them can add depth to your appreciation of this American icon.
