In wine analysis, aromas and flavors are divided into three broad categories: Primary, Secondary, and Tertiary. Primary aromas are those that you perceive first, and so on.
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, where they originated from in the overall winemaking process. Primary aromas and flavors come from the grapes themselves and remain unchanged in the wine. Pyrazines (those green bell pepper aromas and flavors), for example, are primary aromas/flavors. Secondary aromas and flavors are those that come as a result of fermentation (either the primary alcoholic fermentation or malolactic fermentation). The aroma and flavor of bread dough in Champagne, for example, is a secondary aroma/flavor that results from contact with the lees (spent yeast cells). 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.