Of course jelly jars are not the only ones that are made this way but being as I was just trying to get the last grape jelly out of a jar, the question comes to mind. With the opening of the jar about 25% smaller then the main body of the jar any jelly still clinging to the jar at the top is inaccessible with any normal utensil.
Now I am assuming that there is a reason the jars are made this way so…anyone know what that reason is?
I would assume it is so the diameter of the lid is the same as the diameter of the jar. Multiple jars pack better that way.
Less opening to seal.
I think that’s probably a significant factor - another one is that prior to screw-top lids, jam jars would be sealed by lids that were just crimped into place - the shoulder provides some protection against the lid being accidentally flipped off the jar during handling.
There are jar designs that are entirely straight on the inside - here’s one:
https://www.sainsburys.co.uk/shop/gb/groceries/bonne-maman-apricot-conserve-370g?istCompanyId=1e096408-041f-4238-994e-a7cf46bf9413&istItemId=wxtiaitpwp&istBid=t&gclid=CjwKCAjw_tTXBRBsEiwArqXyMlF-qp0KszMaRZF_u9LAPVJ_tP0okcMlszVrepTddA3wS2NQs2mkvRoCPecQAvD_BwE&gclsrc=aw.ds&dclid=CIvUua7H_toCFcxEGwodqOwGBw
[old person mode]
Back in my day some jelly jars were completely smooth/straight sided. The lid popped off. No threading on the top. The apple jelly we used when I was a kid is the one I most remember being like this.
This made them ideal for reuse as glasses by the economy minded.
[/old person mode]
I do think having the top inset a little bit does help with shipping. It might even reduce breakage as you don’t have metal to metal banging at the top which might break the jars or break the vacuum seal.
The pop-off type lids might not have been as good a sanitary seal.
You see this as a problem. I see it as an opportunity for you to invent a utensil designed to get that last little bit of jam out of the jar. You could build a fortune on the idea.
I just use a small silicone spatula - it works fine.
Specialist knives also already exist:
Yeah really. I’m not seeing why any of these would not be acceptable. Especially the third one pictured. One or another of these are what we use when the last bit of peanut butter or jelly are clinging to the container. Gets at least three or four more sandwiches worth.
As a kid, I always found that the finger worked well for this. And you then popped it into your mouth (so that jam isn’t wasted), there was no extra utensil that had to be washed.
What? Didn’t you wash your finger?
Not until Mom made me take a bath that night. And since that was going to happen anyway, it wasn’t any ‘extra’ washing.