“Vintner” means a winegrower, as defined in Section 23013 of the Business and Professions Code, who holds a winegrower’s license issued by the Department of Alcoholic Beverage Control pursuant to Chapter 3 (commencing with Section 23300) of Division 9 of the Business and Professions Code, and who is engaged in producing must, grape juice, grape concentrate, wine, or products thereof, including high proof and brandy by processing winegrapes or field crushed must.