WSET Diploma D2 Practice Exam

The key idea is how yeast metabolism and the conditions you manage during fermentation shape the aroma compounds that end up in the wine. Yeast nutrients provide the building blocks and cofactors for metabolism, so their availability directly influences the formation of aroma-active compounds. When nutrients like assimilable nitrogen are plentiful, yeast can channel carbon and amino-acid metabolism into the production of esters and higher alcohols, which are major contributors to fruity and floral aromas. In contrast, nutrient limitations can push metabolism toward other byproducts and reduce the overall aroma output.

Fermentation management adds another layer. Temperature affects enzyme activity that drives ester formation and the production of volatile compounds; different temperatures favor different aroma profiles and influence how completely fermentation finishes. Oxygen, controlled early in fermentation, supports yeast membrane function and sterol synthesis, which also shapes how efficiently the yeast ferments and which aroma compounds are produced. Together, nutrient status and fermentation management sculpt both the intensity and the character of the aroma, as well as whether the fermentation ends cleanly and completely.

Other statements miss important aspects. Color stability isn’t the primary factor here and is more about phenolics and pigments, while aroma is indeed influenced by nutrient levels and fermentation conditions. Saying aroma isn’t influenced by these factors ignores the central role of yeast metabolism in aroma development.