In contrast to the previous chapters, which consider wine compounds common to all alcoholic beverages, these chapters detail the (bio)chemical reactions that transform grape‐derived precursors into (varietal) secondary and tertiary aroma compounds. The subsequent sections describe:
- Biosynthesis of glycosides in the berry, their extraction, and hydrolysis during fermentation and aging
- Formation of S‐conjugates (thiol precursors) pre‐ and post‐harvest, cleavage during fermentation, the concept of sulfur mass balance and alternative pathways to thiol formation
- Conversion of other grape components – polyunsaturated fatty acids (C6 volatiles), hydroxycinnamic acids (Brettanomyces and volatile phenols), and S‐methylmethionine (dimethyl sulfide).