Citrus.

Citrus oils are cold-pressed from the rind of bergamot, lemon, lime, grapefruit, orange and mandarin. They are the brightest and briefest notes in perfumery — usually evaporating within minutes — but they are also the most universally loved opening. Almost every perfume begins with a citrus accent.

Modern fixatives (Ambroxan, Iso E Super) can extend a citrus far beyond its natural lifespan, allowing genuine citrus colognes to last six hours rather than thirty minutes.