In the context of a wine evaluation (judging) or wine address (describing), we sometimes speak of four different olfactory sensations that can be perceived one after the other when tasting:
Without swirling the glass, only sniff briefly and lightly without inhaling too deeply. This allows the particularly volatile aromas to be perceived and gives a first indication of the type and complexity of the wine.
By swirling the glass (see also under Enjoying Wine), further aromas are released. Any wine defect that may be present is now also intensified or only now perceived.
For me, Lexicon from wein.plus is the most comprehensive and best source of information about wine currently available.
Egon Mark
Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)