Headspace, and getting the air out

Headspace

Half an inch is the usual figure for pickles, and it is a specification rather than a guide. Too little and the contents interfere with the seal as they expand; too much and there is more air than the process can deal with. Either way the failure shows up as a jar that did not seal, or one that seals and then does not hold.

Measure it rather than eyeballing it, at least until the eye is trained against a measured jar. At volume this is one of the places consistency quietly disappears.

Trapped air

Pack a jar of spears and air stays between them. Run a non-metallic tool down the inside to release it, then re-check the headspace, because removing air drops the level. The tool is specified as non-metallic for the same reason the rest of the process is: metal in acid brine is a darkening cause, and a tool that touches every jar is a good way to spread one mistake across a whole run.

Then the rim

Wipe it before the lid goes on. A trace of brine on the rim is a seal failure waiting to happen, and seal failures found after cooling cost more than the seconds spent on a cloth. This is the step that disappears first when a packing day runs late, and it is the one that produces a pattern of failures rather than a single one.

All three of these are seconds per jar, which is exactly why they go first under time pressure and exactly why they should be built into the pack rate rather than treated as finishing touches. A run that was sized to leave time for them does not have to choose.

References