Capping
Updated
The last step and the one done carelessly because the interesting part is over.
When
Once the stick is firm through, not when the surface has set.
Capping a warm tube traps warm air and condenses nothing useful onto the balm, and on a hot day it softens the top back into contact with the cap so the stick comes away with it.
Wind down first
Every tube goes out wound fully down. A stick standing proud gets flattened by its own cap in a box.
It is also the check that the mechanism works, which is worth doing on every unit rather than sampling, because a seized elevator is a returned tube and takes ten seconds to catch here.
The cap is part of the product
A cap that does not seat is a tube that opens in a handbag. A cap that is too tight cracks a thin tube when a customer twists rather than pulls.
Caps and tubes from the same supplier and the same range fit. Mixing a cheap cap onto a different tube is a false economy that shows up as complaints about the product rather than the cap.
It also seals the headspace, which is what slows flavor loss and oxidation once the tube leaves you.
Checking a run
Cap, then look along the tray. Uncapped, crooked and short-filled tubes are all visible in one pass and invisible once they are in a box.
Then pull the first, middle and last of the run and keep them. That is your reference set for the batch, and the only way to answer a complaint three months later with anything other than an apology.