The fill level tells you more than the label
Before the cork is ever drawn, a serious bottle has already confessed most of its life. You only have to know where to look — and the first place is the space between the wine and the cork.
It is called ullage: the small gap of air at the top of the bottle, and the height of the wine within the neck and shoulder. To the untrained eye it means nothing. To anyone who has handled enough old bottles, it is the single most honest thing a wine will tell you about how it was kept. A young wine should sit high in the neck. For a bottle of twenty years or more, a fill into the top of the shoulder is the mark of exceptional storage — cool, still, and undisturbed for decades. The lower the level falls, the more the bottle has breathed; and a wine breathes fastest when it has been warm. So a fill that is too low for the vintage whispers of heat, of movement, of a cellar that was not what it claimed. And a fill that is suspiciously high in an old bottle whispers of something worse — a wine topped up, or never as old as the label insists. This is why a case kept in one place, at one temperature, since release matters so much: identical conditions produce identical, stable fills across every bottle. A case where the levels vary from one bottle to the next has a story it would rather not tell.
One caution, though, because it separates those who have handled old bottles from those who have only read about them: this reading of neck and shoulder belongs to the Bordeaux shape. A Burgundy bottle slopes too gently to mark a shoulder at all, so its ullage is measured plainly, in centimetres from the cork — and Burgundy, by its nature, forgives a little more air than Bordeaux does. The same gap that would worry you in a claret can be unremarkable in an old red Burgundy. Read the level, but read the bottle first.
The label states the maker and the year. The fill level states the truth. We have learned to read both, and to trust the second one more.