Primary wine aromas come directly from the grapes themselves and vary between different grape varieties. They consist of scents from fruits, flowers and herbs. On the molecular level, you'll find different varieties of aroma compounds in different wines. These compounds effectively mimic the odor molecules of the fruits or herbs that they smell like.
Secondary aromas are created by the fermentation process. These aromas can include yogurt, mushrooms or even bacon. A wine's secondary aromas depend on the type of yeast used for fermentation and, in some cases, the aging process itself.
Aging is also the main factor in a wine's tertiary aromas. Exposing a wine to oxygen is a crucial step and brings in the aromas of different nut varieties. Another way to bring aromas in is to use oak barrels, which import notes of vanilla or cedar. Cooking a wine brings in aromas such as caramel or butterscotch.
Now test your nose with a wine fit for the test - a Brunello di Montalcino.