California Code, Business and Professions Code - BPC § 23390

(a) A licensed winegrower or brandy manufacturer, in addition to exercising all the privileges of their license at their licensed premises, may exercise all the license privileges at or from branch offices or warehouses, or United States bonded wine cellars located away from the place of production or manufacture, other than the following privileges:

(b) The department may issue to a winegrower or brandy manufacturer a duplicate of the original license for a location or locations other than the wine production or brandy manufacture premises. The duplicate license authorizes the maintenance and operation of each branch or warehouse or United States bonded wine cellar declared and designated by the winegrower or brandy manufacturer at the location for which the duplicate license is issued.

(c) Notwithstanding any other law, the department may allow any person that held more than one original winegrower's license, on or before January 1, 1981, to transfer any duplicate license which has been issued, on or before January 1, 1981, on any of the original winegrower's licenses to any other original winegrower's license held by that person, on or before January 1, 1981, provided that the licensee cancels the original winegrower's license from which any duplicate license is transferred. This subdivision shall not authorize any person to acquire any additional duplicate licenses other than those held by that licensee on or before January 1, 1981.