Exhibit 10

Domaines Barons de Rothschild (Lafite) SCA

33, rue de la Baume

75008 Paris

France

September 10, 2004

Board of Directors

The Chalone Wine Group, Ltd.

621 Airpark Road

Napa, CA 94558

Gentlemen:

We are writing on behalf of ourselves (“DBR”), as well as Constellation Brands, Inc. (“CBI”) and Huneeus Vintners LLC (“HVI”, and together with ourselves and CBI, the “Partners”), in reference to the offer letter sent to you on May 17, 2004 (the “Offer Letter”) proposing a business combination transaction to The Chalone Wine Group, Ltd. (the “Company”) and the letters dated June 30, July 31, August 20, August 27, and September 3, 2004 indicating extensions of that offer (the “Extension Letter,” the “Second Extension Letter,” “Third Extension Letter,” “Fourth Extension Letter,” and “Fifth Extension Letter,” respectively).

The Fifth Extension Letter stated that the proposal contained in the Offer Letter would remain open for your consideration until September 10, 2004. We hereby extend the duration of the proposal until September 17, 2004. The remaining terms of the Offer Letter remain in full force and effect.

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