Almost everyone knows Chanel No. 5, and the champagne-like ‘whoosh’ you get at first sniff: that fragrance was one of the earliest uses of these synthetic ingredients, which took perfumery into a whole new dazzling era. Aldehydes turbo-charge a fragrance, sometimes giving an almost fizzy first impression. They’re not exclusive to floral fragrances (aldehydes can be added to almost any fragrance, including chypres and ambrées), but they’re most often used to add dazzling brightness to florals. Later, after a floral aldehydic fragrance ‘settles down’, the impression can often be powdery.