“Vintner” and “processor” are synonymous and mean any person engaged in producing must, grape juice, grape concentrate, wine, or products thereof, including high proof and brandy, and includes a “winegrower” as that term is defined in Section 23103 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. A vintner who acquires and processes winegrapes in the preceding marketing season in a quantity of 100 tons or less is not subject to this chapter.