The batch number is a column in the bottling control log and at the same time the code that has to reach the bottle: visible, legible and indelible.
Where: WineryElf menu → Bottling → the log for the year → Add entry
Where to enter it
When adding a bottling entry, next to the date, there is a Batch no. field. Enter the same number you print on the label. If it cannot be told apart from the rest of the labelling, prefix it with the letter L (for example L2605A).
The number shows in the entry table and on the log printout.
Older entries
Entries added before this column existed show a dash. You can fill them in by editing - the change is kept in the correction history, so the trail remains. The application never backfills numbers on its own, because it cannot guess which batch matched which bottling run.
Why it matters
The batch number ties a bottle standing at a customer to a specific entry in the log: bottling date, volume and the wine batch behind it. It is the basis for a recall if something goes wrong, and the first thing asked for when a complaint arrives. In jurisdictions with label integrity rules it is also part of the one-step-forward, one-step-back traceability you are expected to keep.