The winery is located in the municipality Saint-Estèphe or the same area in the Médoc (Bordeaux). From the famous Château Lafite-Rothschild it is only separated by a stream. Part of the vineyards was dissolved in 1789 and thus the Château Cos Labory founded. The founding year of the Château Cos d'Estournel is 1811, when the horse and wine merchant Louis-Gaspard d'Estournel (1753-1844) acquired the first vineyards. He recognized the quality of the extremely barren pebble soils (Cos) early on. The name part "Cos" (Caux) is derived from "Colline de cailloux" (gritty hill). Louis-Gaspard d'Estournel exported his wine to India and Arab countries. From there he imported noble horses, which were bred in the pastures around the vineyards. He built a huge, partly Asian-style wine cellar, including the pagoda-like curved rooftops and the famous door from the harem area of the Sultan of Zanzibar.
Estournel discovered by chance the value of the voyage of the wine in wooden barrels when unsold wine was returned from India. He compared it to the same wine left behind and noted a significant improvement in quality. When selling these achieved far better prices. Therefore, after some time, all wines were sent on a voyage before being sold and marked with an "R" (return of Indes = back from India). One could therefore consider him as one of the "inventors" or at least first user of the Aged expansion denote (if these barrels already toasted were, is not known). In the medium term, this complex procedure led to a financial fiasco. Therefore, the estate was sold in 1852 to the London banker Martyns. In the Bordeaux Classification In 1855, the Château was then ranked second under the name "Cos Destournel" (Deuxième Cru Classé).
After a rich history, in 1970 the estate was inherited by Yves, Jean-Marie and Bruno Prats, The latter acted until 1998 as managing director. During this time, the term "Super-Seconds" was born in the Médoc. This means that the wine would deserve the "Premier Cru Classé" because of its high quality. This was thanks to Bruno Prats, who worked with tremendous perfection and the most modern methods. 1998 was the good to the Taillan Group and finally sold to food manufacturer Michel Reybier in 2001. Today it is managed by Prat's son Jean-Guillaume.
The total property covers 100 hectares, of which 67 hectares are planted with vines. These are Cabernet Sauvignon (60%), Merlot (38%) and Cabernet Franc (2%). The extremely long-lived red wine matures 18 to 24 months in 70% to (in particularly good years) 100% new barriques, The second wine is called "Les Pagodes de Cos". The "Maître d'Estournel" brand wine produced under the "Bordeaux" appellation was created in 1971 by Bruno Prats. The name honors the legendary founder Louis Gaspard d'Estournel. The red wine is made from the varieties Cabernet Sauvignon, Merlot and Cabernet Franc, the white wine from Sauvignon Blanc, the grapes come from the whole region. These are priced significantly cheaper wines.