Headspace, and getting the air out of a thick sauce

Why it matters more here

Trapped air is a void, and a void is a place the process does not heat the way it heated the product around it. It also drops the fill level after sealing, which reads to a customer as a short fill, and it carries oxygen that works on color and flavor across the shelf life.

Releasing it

Run a non-metallic tool down the inside of the jar and around, then re-check the headspace, because releasing air drops the level and the jar you measured is no longer the jar you have. The tool is specified non-metallic for the same reason the rest of the process is: metal in an acid product is a darkening cause, and a tool that touches every jar spreads one mistake across a whole run.

Headspace is a specification

It comes from your filed process, and it is not a preference. Too little and the contents interfere with the seal as they expand; too much and there is more air than the process was designed to deal with. Measure it rather than eyeballing it, at least until the eye has been trained against a measured jar.

Then wipe the rim

A thick sauce on a rim is worse than a thin one, because it does not run off and it is easy to miss. A trace of product under a lid is a seal failure waiting to happen, and seal failures found after cooling cost more than the seconds spent on a cloth.

All three of these are seconds per jar, which is exactly why they go first under time pressure and exactly why they belong in the pack rate rather than being treated as finishing touches.

References