This is a concept that is often misunderstood. The three categories of primary, secondary and tertiary aromas and flavors do not indicate the timing of when you perceive them, but rather, when they were introduced into the winemaking process. Primary aromas and flavors come from the grapes themselves and remain unchanged in the wine. Pyrazines (green flavors), for example, are primary aromas/flavors. Secondary aromas and flavors are those that come as a result of fermentation. The aroma and flavor of bread dough in Champagne, for example, is a secondary aroma/flavor that results from time spent on the yeast lees after fermentation. And finally, tertiary aromas and flavors are those that come as a result of a wine’s storage or aging.  Wines stored in oak barrels, for example, possess aromas and flavors (vanilla, baking spices, roasted coffee notes etc.) attributable to the oak.