Hello, I've canned several batches of mango jam in the past, always in 8 oz jars. All very routine and the lids always popped down on their own.

I decided to make a batch with (12) 4 oz Ball jars (silver lids.) Not a lid popped down on its own. However, hours later with a a very light press every lid did pop down on its own and, the important part- stayed down. And upon removing the bands a day later I could lift every jar by the lid and apply some upward force to the lid to verify the lids stayed on. I'm going to call that a successful seal (but tell me if I shouldn't.) I'll also watch them for a few days just to make sure the the lids don't pop up.

I'd rather have the lids pop down on their own though- it is more mentally reassuring. Just curious if anyone has had a similar experience.

Thanks!