Kerr Mason jars‚ iconic symbols of home canning and preservation‚ hold a fascinating history. Determining a jar’s age isn’t always straightforward‚ but with a keen eye and understanding of key features‚ you can often pinpoint its manufacturing period. This guide provides a detailed look at dating these beloved jars.
Why Date a Kerr Jar?
Beyond simple curiosity‚ knowing a jar’s age can add to its collectible value. Older jars‚ particularly those in excellent condition or with unique markings‚ are often highly sought after by collectors. Understanding the history also provides insight into canning practices and societal trends of the time.
Key Features to Examine
Several elements contribute to dating a Kerr jar. Focus on these:
Logo & Markings
Early Kerr Jars (pre-1910): These often feature a simple “Kerr” logo‚ sometimes with a city of origin (e.g.‚ “Kerr‚ Newell‚ PA”). Look for embossed lettering. The glass itself tends to be slightly less refined.
1910-1930s: The logo evolved‚ becoming more stylized. You’ll see variations including “Kerr Mason Jar” and the introduction of the diamond “K” logo. Markings may include patent dates. This period saw increased standardization.
1930s-1960s: The diamond “K” logo became dominant. Jars from this era often feature the “Ball-Fast” closure system‚ indicating a later production date. Color variations (clear‚ amber‚ green) became more common.
Later Years (1960s-Present): The logo continued to evolve‚ and jars increasingly featured modern closures. Focus shifted towards efficiency and mass production.
Closure Type
The type of lid and closure system is a crucial dating indicator:
- Glass Lids & Wire Bales (pre-1915): These were the earliest closures‚ requiring a separate glass lid and wire bale to secure it.
- Weck Jars (early 20th Century): Though not exclusively Kerr‚ similar glass-on-glass closures were used.
- Two-Piece Metal Lids (1915-Present): The introduction of the two-piece metal lid (flat lid and screw band) revolutionized canning.
- Ball-Fast Lids (1930s-1960s): A specific type of two-piece lid‚ often found on Kerr jars from this period.
- Modern Screw-Top Lids (Present): The standard today.
Jar Shape & Size
While not definitive‚ jar shape and size can offer clues. Early jars tended to be more varied in shape. Standardized sizes became more prevalent in the 20th century. Common sizes include pint‚ quart‚ and half-gallon.
Glass Color & Quality
Early jars often have a slightly greenish or bluish tint due to impurities in the glass. Clear glass became more common with advancements in manufacturing. The overall quality of the glass – its thickness and clarity – can also indicate age.
Resources for Further Research
- Red Book of Fruit Jars: The definitive guide for jar collectors.
- Online Forums & Communities: Websites dedicated to antique jars offer valuable information and expert opinions.
- Antique Shops & Auctions: Examining jars in person can help you develop an eye for identifying age and authenticity.
