Hennessy XO (Extra Old) Cognac is a blend of up to 100 eaux-de-vie, with the youngest component aged a minimum of ten years in French oak and the oldest components drawn from Hennessy's library reserves. XO as a cognac classification was first established in the 19th century — Hennessy created the category for private use before it became a regulated designation. Each eau-de-vie in the XO blend is double-distilled in Charentais copper alembic stills and aged in Limousin or Tronçais French oak. The extended ageing develops characteristic notes of dark chocolate, candied fig, leather, dried flowers, and rich, structured oak. Bottled at 40% ABV.

Hennessy was founded in 1765 by Richard Hennessy, an Irish officer who had served in the French army and settled in Cognac, Charente. The house grew through the 19th century to become one of the world's largest cognac producers and is now a founding member of the LVMH group. Hennessy sources eaux-de-vie from across all six growth areas of the Cognac region — Grande Champagne, Petite Champagne, Borderies, Fins Bois, Bons Bois, and Bois Ordinaires — and maintains a library of over 350,000 barrels in its Cognac cellars. The blending tradition at Hennessy has been held by the Fillioux family for eight successive generations.