Cos d'Estournel is a vineyard and winery in the Saint-Estèphe appellation of the Médoc. In the 1855 Classification, it was classified as a second growth and remains one of the most prominent and sought-after of all Bordeaux wines. Historically, the Cabernet Sauvignon-dominant grand vin has had a high percentage of Merlot compared with other Médoc growths, although this has lessened in recent years. Cos d'Estournel is dark, brooding and tannic when young, developing complexity and intensity with time.