what causes a false seal?

[Pray4bestP4w]

I check my pressure canned jars once a week, mainly because I'm new to canning and I've probably read way too many online canning articles.

Today as I was checking the jars, one of my canned oranges lid popped off easily. I then doubled checked all the other jars and with the exception of this jar, all the lids are sealed & show the concaved dimple in the lid. By the way, there is no mold/growth on the oranges or syrup in the jar.

I allow all of my canned jars to sit for 24 hours after pressure canning, and check the seals before I wash & label them and take them to the basement (temperature is monitored between 59 - 61 degrees).

Because of my over education of Botulism and a bit of OCD, I follow Ball's Blue Book directions for pressure canning diligently.

Was this jar of canned oranges an example of a false seal? If so, what causes a false seal? If not, what did I do wrong?

[Molly53]

According to the Ball/Kerr company: Using current home canning jars, lids, bands, processing methods and times all help assure there is no seal failure or that unsealing does not occur. It is important to follow the manufacturer’s instructions when preparing jars, lids and bands for use. It is also important to examine the canner to be certain it is in good working condition. When home canning, always use an up-to-date, tested recipe from a reliable source.

If seal failure or unsealing does happen, check the following points to determine if one of them is the cause:
• Insufficient or incorrect processing;
• Over-tightening the band before processing or re-adjustment of the band after processing;
• Incorrect headspace;
• Reusing lids;
• Using commercial jars;
• Not preparing lids for use according to manufacturer’s instructions;
• Not removing air bubbles from the jar or cleaning the rim of the jar before applying the lid.

[Pray4bestP4w]

Thank you for your reply. I 'think' I reused a lid from previous canning when I ran out of the new jars, lids & bands box while filling the orange sections. Lesson learned. I have to come up with a better organization for my used lids (keeping separate from the new complete jars.)

And yes, I'm getting more feed back from this site than the other canning sites (New Years Eve, I guess so a big THANK you!!

[Zeldaz]

I mark any used lid with a Sharpie to make sure I know it can't be processed again.

[Molly53]

That's a great idea, Z.

[Pray4bestP4w]

Well great minds think alike My mom suggested same thing yesterday.

Thank you for replying to my problem. I wish you a happy new year!