Cognac is culturally a blend of eaux-de-vie from different years, of different ages, depending on the qualities sought by the Cellar Master.
However, it can happen that a harvest year presents particular characteristics (sunshine, drought, etc.) and that the eaux-de-vie from this harvest are not intended to be blended in order to highlight their specificity.
In order to ensure the authenticity of the year of these eaux-de-vie, great rigour is applied in the monitoring of their ageing by the BNIC. In order to be monitored as "Vintage", these eaux-de-vie are generally aged in a cellar dedicated to this purpose: this cellar is locked with a unique key, and only the BNIC keeps it. If the winegrower cannot dedicate a room for this purpose, the casks are sealed with wax.
No intervention on these future Cognacs can be made without the presence of a BNIC representative. Nothing can be added to or taken from these casks; man has no influence on their ageing, he can only watch over them.
All these special conditions make Vintage Cognacs rare beverages, and when bottling takes place, the number of bottles is very limited!