Château Cos d'Estournel is one of Bordeaux's most celebrated estates, classified as a Second Growth (Deuxième Cru) in the historic 1855 Bordeaux Classification. Located in Saint-Estèphe, the northernmost of the four great communes of the Médoc, this wine is produced from a 100-hectare vineyard planted on the hill of "Cos," a Gascon word meaning "hill of pebbles." The estate was founded in 1811 by Louis Gaspard d'Estournel and is now owned by Michel Reybier. The château became fully organic in 2024.

This red Bordeaux blend is typically composed of approximately 56–65% Cabernet Sauvignon, 33–40% Merlot, and small amounts of Cabernet Franc and Petit Verdot, with vines averaging 55 years of age. Winemaking at Cos d'Estournel is meticulous: grapes are cold-macerated, fermented at low temperatures to avoid over-extraction, and aged in 50–60% new French oak barrels for approximately 18 months before bottling. The winery operates entirely by gravity — no pumps are used — in order to preserve the purity and integrity of the fruit.

The wine is known for its rich, powerful, and age-worthy character, with distinctive aromas of dark currants, Asian spices, licorice, incense, smoke, and dark chocolate. Experts recommend decanting young vintages for 2–4 hours and cellaring bottles for 15–40 years to reach peak maturity. This 3-liter format (equivalent to four standard bottles) is ideal for long-term cellaring, as larger formats age more slowly and gracefully.

Cos d'Estournel pairs beautifully with red meat, lamb, duck, game, roast chicken, and grilled dishes, as well as Asian cuisine, mushrooms, and pasta. Serve at approximately 15.5°C (60°F).