Wide mouth, and why it is not optional

Two jobs, both needing width

Getting product out, and getting a knife in to recombine oil that separated. A narrow mouth makes both awkward, and the second one is the reason a jar that merely admits a knife is not wide enough. The buyer needs to reach the bottom corners.

What the shelf holds

The jars that qualify for this use are all glass, 89 to 946 ml, with the mouths deliberately wide. The common finishes are 63TW, 58-400, 70-450G and 58TW among others, and there are 238 closures verified against them. Every container page lists the closures checked against its own neck rather than leaving the match to you.

Straight sides beat a shoulder

A shouldered jar has a wide body and a narrower opening, which traps product where a knife cannot reach. On a product that separates, that corner never gets stirred back in and the last part of the jar is dry and crumbly. A straight-sided jar does not have the problem.

Filling is easier too

A thick product fills slowly through a narrow opening and tends to trap air pockets against the glass that look like defects from outside. A wide mouth fills faster and cleaner, which at volume is a real difference in how long a run takes.

The rim has to stay clean

Thick product does not run off a rim the way a thin one does, so any smear sits between the glass and the liner. A rim wipe is part of the fill on this product, not a tidiness step, and a wide mouth makes it possible to do properly.

References