The influence of microorganisms on winemaking begins in the vineyard and develops through fermentation and storage or aging of the wine. Grapes arriving at the winery refl ect not only the condition of fruit at harvest but also the method of harvest and transport time. As visually defect-free fruit harbors yeasts (Section 6.2.1), molds (Section 4.2), and bacteria (Sections 6.4.1 and 6.5.1), it is important to use processing protocols that minimize the potential for further growth of undesirable native microflora.