Smell is the most important sense in wine tasting. Its sensitivity is ten thousand times higher than that of taste, and thanks to it we can perceive the volatile components of wine.
The olfactory analysis is the second test wine has to undergo before reaching the mouth. The different aromas and nuances will give us the background on the grape variety, production and aging system, age and evolutionary state.
Of the many wine components (between 800 and 1,000), only about 50 are in sufficient concentration to be perceived by the human nose, and they are not together. In a young wine we may find about 25, and about 40 in more complex wines.
Aromas are divided into primary, secondary and tertiary, depending on their origin:
Primary are fruity and floral aromas, typical of the grape type they come from.
Secondary are those originating from alcoholic and malolactic fermentations. They are not always positive aromas, that, in many cases, disappear with simple aeration of the glass.
Tertiary are produced by oxidation or reduction in the wine aging process, either in barrel or bottle. All together is called bouquet.
The bouquet is the heritage of a wine subject to aging, but it will also show the variety of primary aromas and the secondary related to vinification being, therefore, the sum of the three. Thus it is not correct to speak of bouquet when referring to a young wine, since it will only have primary and secondary aromas.