Top notes: Scents that are perceived a few minutes after the application of a perfume. Top notes create the scents that forms a person's initial impression of a perfume. Because of this, they are very important in the selling of a perfume. The scents of this note class are usually described as "fresh", "assertive" or "sharp". The compounds that contribute to top notes are strong in scent, very volatile, and evaporate quickly. Citrus and ginger scents are common top notes.