Chanel No 5 went on sale on 5 May 1921 with a bigger dose of aldehydes than any perfume before it. More than a century later, most people who love that perfume still cannot say what an aldehyde is. Here is the plain version.
An aldehyde is a small organic molecule with a reactive CHO group at one end. Perfumery mostly uses one branch of the family, the fatty aldehydes, and names them by carbon count. Aldehyde C-10, decanal, has ten carbon atoms and smells of orange peel and candle wax. C-11 and C-12 smell of snuffed candles, starched linen and soap. On their own they are odd, almost greasy. Dosed into a floral, they lift everything, like turning up the brightness on a photograph.
That lift is what you smell in No 5. Ernest Beaux, the French-Russian chemist who built it, set C-11 and C-12 aldehydes over rose and jasmine. Tilar Mazzeo's biography of the perfume tells the famous version of how the dose happened: a lab assistant mistook a full-strength aldehyde mixture for a ten per cent dilution and jolted the formula with a quantity never used before. Beaux's student Constantin Weriguine said the result had the clean note of the Arctic, "a melting winter note". Coco Chanel smelled the numbered samples and picked number five.
Now the bit the legend leaves out. No 5 was not the first aldehydic perfume. Houbigant's Quelques Fleurs used aldehydes in 1912, nine years earlier, and Beaux worked openly from that starting point. No 5 was simply the loudest, and the loudest one won.
One more receipt. The material sold as aldehyde C-14, the famous peach note, is not an aldehyde at all. It is gamma-undecalactone, an eleven-carbon lactone that picked up its trade name before chemical naming settled down. Wrong family, wrong number, and the name stuck anyway.
So what does "aldehydic" mean on a bottle today? Soapy, waxy, sparkling, slightly retro, the smell of expensive clean. If a perfume smells of cold air and pressed shirts in its first minute, aldehydes are usually why.
We use that sparkle twice. Elixir Force, our take on YSL's Y Elixir, runs aldehydes over lavender and bergamot at 35% Extrait. Vanilla Bliss, our take on Dior's Vanilla Diorama, uses them to put fizz on Madagascar vanilla. More in the best YSL dupes in the UK.
