Vanillin is most prominent as the principal flavor and aroma compound in vanilla. Cured vanilla pods contain about 2% by dry weight vanillin. On cured pods of high quality, relatively pure vanillin may be visible as a white dust or "frost" on the exterior of the pod.
It is also found in Leptotes bicolor, a species of orchid native to Paraguay and southern Brazil, and the Southern Chinese red pine.
At lower concentrations, vanillin contributes to the flavor and aroma profiles of foodstuffs as diverse as olive oil, butter, raspberry, and lychee fruits.
Aging in oak barrels imparts vanillin to some wines, vinegar, and spirits.
In other foods, heat treatment generates vanillin from other compounds.  In this way, vanillin contributes to the flavor and aroma of coffee, maple syrup, and whole-grain products, including corn tortillas and oatmeal.