“Vintner” and “processor” are synonymous and, except as otherwise specifically provided in this chapter, mean any person engaged in Mendocino County in producing or causing to be produced must, grape juice, grape concentrate, wine, or other winegrape products, including high proof and brandy, and includes a “winegrower” in Mendocino County as that term is defined in Section 23013 of the Business and Professions Code, who produces wine from winegrapes. However, a producer does not become a vintner solely by the act of field crushing winegrapes before delivering the winegrapes as must to another person.