What it actually is
A coating is held on by a hydrated bridge between a wet product surface and a dry crumb. The pre dust absorbs surface moisture and roughens the surface, the batter keys into it, and the crumb keys into the batter. Each layer holds the next. Where that chain breaks, the coating leaves.
Why it matters
Every gram of crumb that falls off is yield already paid for, and a product that arrives half coated is rejected on sight. The cost appears twice: once in the fryer and once in the complaint.
What changes it
Surface moisture before coating, pre dust choice, batter viscosity, and the freezing profile. Most adhesion failures are created during freezing and storage rather than during coating, because moisture continues to migrate outward from the core long after the line has stopped.
