How to Date Kerr Mason Jars? A Guide to Understanding Vintage Canning
Dating Kerr Mason jars involves deciphering a combination of logo styles*, jar *shapes*, and *embossing characteristics. These features, when analyzed together, provide clues to narrow down the production era of your antique or vintage canning jar.
Introduction: The Allure of Antique Canning Jars
Canning jars are more than just vessels for preserving food; they are tangible links to the past, representing generations of home cooks and agricultural traditions. Among the most popular and collectible brands are Kerr Mason jars. Understanding how to date these jars allows collectors and history enthusiasts to appreciate their heritage and identify their value. Dating Kerr jars isn’t an exact science, but by carefully examining specific features, you can significantly narrow down their production timeframe.
Why Date Your Kerr Jars?
Dating your Kerr Mason jars isn’t just a fun hobby; it also provides several practical benefits:
- Determining Value: The age and rarity of a jar greatly influence its value to collectors.
- Historical Context: Knowing the age helps you understand the historical period in which the jar was produced and used.
- Authenticity Verification: Dating can help identify reproduction jars that are not authentic antiques.
- Completing Collections: If you are a collector, accurate dating helps you fill gaps in your collection with jars from specific eras.
- Personal Connection: Discovering the age of a jar can create a stronger connection to the past and the people who used it.
The Key Elements: Unlocking the Jar’s Past
Several characteristics of Kerr jars provide valuable clues about their age:
- Logo Style: The font, design, and placement of the Kerr logo are significant indicators.
- Jar Shape: Different jar shapes were popular in different eras.
- Sealing Method: The type of closure (e.g., wire bail, zinc lid, two-piece lids) provides a general timeframe.
- Embossing Characteristics: The style, size, and clarity of the embossing provide valuable dating clues.
- Glass Color: While less reliable than other factors, the color of the glass can sometimes offer clues.
Deciphering the Kerr Logo: A Chronological Journey
The Kerr logo underwent several changes throughout the company’s history. Recognizing these variations is crucial for dating your jars:
- Early Logos (Pre-1903): These were often more elaborate and included depictions of fruits and vegetables.
- Simplified Logos (1903-1915): Simpler, more streamlined designs began to emerge, focusing on the Kerr name.
- The “Self Sealing” Era (1915-1960s): This era features the prominent phrase “Self Sealing” as Kerr innovated its closure systems. This logo often includes the word “Mason”.
- Modern Logos (Post-1960s): These are typically very clean and modern, often featuring a simple “Kerr” in a standard font.
Here’s a table summarizing the logo timeline:
| Period | Logo Characteristics |
|---|---|
| Pre-1903 | Elaborate, often with fruits/vegetables |
| 1903-1915 | Simplified, focused on the Kerr name |
| 1915-1960s | “Self Sealing” prominent, included “Mason” |
| Post-1960s | Clean, modern, simple “Kerr” |
Jar Shape and Design: Evolving Styles
The shape of Kerr jars also evolved over time. Early jars were often more irregular and handmade, while later jars became more standardized. Certain shapes were also more popular during specific periods. Researching historical canning jar catalogs can provide valuable insights into the popular styles of different eras.
Examining the Embossing: Reading the Fine Print
The embossing on Kerr jars is a treasure trove of information. Pay attention to:
- Font Style: The font used for the embossing.
- Size of the Letters: The size of the embossed letters.
- Clarity of the Embossing: How sharp and well-defined the embossing is.
- Wording Used: The exact wording used in the embossing, including any patent dates or other markings.
Common Mistakes to Avoid
Dating Kerr jars can be tricky, and it’s easy to make mistakes. Here are some common pitfalls to avoid:
- Relying on a Single Factor: Don’t rely solely on one characteristic, such as the logo style. Consider all available clues.
- Ignoring Seam Marks: Examine the seams on the jar. Early jars often had visible mold seams that extended to the top.
- Misinterpreting Imperfections: Don’t assume that all imperfections indicate age. Modern reproductions may be intentionally distressed.
- Ignoring the Closure Type: The type of closure is critical to consider.
Finding Reliable Resources
Many online resources and books can help you date your Kerr jars. Reputable collector websites and historical societies can provide valuable information.
Frequently Asked Questions (FAQs)
What is the significance of the “Self Sealing” phrase on Kerr jars?
The phrase “Self Sealing” indicates that the jar was made after Kerr patented its self-sealing lid in 1915. This is a crucial marker when determining a jar’s age.
Can the color of the glass reliably determine the age of a Kerr jar?
While glass color can sometimes be a factor, it’s not the most reliable indicator. Different glass formulations were used at different times, and color variations can also occur due to factors like impurities in the sand or the manufacturing process.
What does it mean if my Kerr jar has a number on the bottom?
The numbers on the bottom of Kerr jars are typically mold numbers used by the manufacturer. These numbers do not directly indicate the age of the jar, but they can be helpful when researching specific jar types and comparing them to known production runs.
How can I tell if my Kerr jar is a reproduction?
Reproduction jars often have subtle differences in the logo, embossing, or glass color compared to authentic antique jars. Look for perfectly smooth seams and uniform glass thickness, which are characteristics of modern manufacturing techniques.
Are Kerr jars with wire bails older than those with screw-on lids?
Generally, yes. Jars with wire bails and rubber rings are typically older than those with screw-on lids. The wire bail closures were common in the late 19th and early 20th centuries before Kerr’s self-sealing lids became widespread.
What resources are available to help me identify my Kerr jars?
Several excellent resources exist:
- Canning jar collector websites: These sites often have detailed information and photos.
- Books on antique canning jars: These books provide historical context and identification guides.
- Antique stores and shows: Experts can help you identify and value your jars.
Does the presence of bubbles in the glass indicate that the jar is old?
While bubbles in the glass can be a sign of older manufacturing techniques, they are not definitive. Modern glassmaking can also produce bubbles. Consider other factors like the logo and embossing to confirm the age.
What is the difference between a “Ball” jar and a “Kerr” jar?
Ball and Kerr were two competing companies that produced canning jars. While both are popular among collectors, they have distinct logos and historical timelines. Ball is well-known for its blue jars, while Kerr is famous for its self-sealing innovation.
What if my Kerr jar has no visible markings or logos?
If your Kerr jar has no visible markings, dating it becomes much more challenging. You may need to rely on the shape and glass color, comparing it to known examples and consulting with experts. However, without a logo, precise dating is nearly impossible.
Is it safe to use antique Kerr jars for canning?
While many people successfully use antique Kerr jars for canning, it’s important to inspect them carefully for cracks, chips, or other damage. Modern jars are designed with specific safety standards for canning, and using antique jars carries a risk of breakage or seal failure. Use caution.
What is the rarest type of Kerr canning jar?
Determining the absolute rarest Kerr jar is difficult, as rarity can depend on condition and geographical location. However, certain early examples with unusual embossing or unique color variations are generally considered highly valuable and rare. Consult with a collector for an accurate appraisal.
How should I clean and preserve my antique Kerr jars?
To clean antique Kerr jars, use warm water and mild soap. Avoid abrasive cleaners or scouring pads, which can damage the glass. To preserve them, store them in a dry place away from direct sunlight. Handle them with care to prevent chipping or breakage.