What does clean smell like? What if the fragrance you want to create is that of a sweet-smelling, yet poisonous, flower? In his Scientific Artistry of Fragrances SCITalk, Dr Ellwood led us by the nose.

When Dr Simon Ellwood spoke about creating a fragrance, it sounded like a musical composition or a painting. The flavourist, sitting before a palette of 1,500 fragrance ingredients. Each occupies a different note on the register: the top notes, the middle ones, and the bottom.

To the outsider, this seems impossibly vast and daunting. The Head of Health & Wellbeing Centre of Excellence – Fragrance and Active Beauty Division at Givaudan mentioned that Persil resolved to come up with ‘the smell of clean’ for its detergents in the late 1950s.

But what should clean smell like? Should it be the green, citrusy aromas of this laundry detergent, the smell of mint, or the antiseptic at the hospital?

To make choosing smells slightly less daunting for flavourists and perfumers, they are at least split into odour families such as citrus, floral, green, fruity, spicy, musky, and woody. Some of these ingredients are natural, some are inspired by nature, and others come from petrochemicals and synthetic materials.

The delicious-smelling musk deer.

Deer gland perfume

One of the smells you may have sprayed on your person – one sibling in this odour family – has peculiar origins. The pleasant, powdery smell known as musk was originally extracted from the caudal gland of the male musk deer and from the civet cat.

But as the Colognoisseur website notes, as many as 50 musk deer would have to be killed to obtain one kilogramme of these nodules. Now, killing a load of deer and cats for a few bottles of perfume may not have seemed unethical several centuries ago, but it also wasn’t sustainable or cost-effective. It became clear that a synthetic musk was needed.

When the synthetic musk discovery came in 1888, it was a chance discovery. Albert Bauer had been looking to make explosives when a distinctive smell came instead, along with the scent of opportunity.

>> Read about the science behind your cosmetics

Dior recreated the woodland notes of Lily of the valley.

Do you like the smell of jasmine?

Dr Ellwood’s talk laid bare not only the vastness of everything we smell, but also the ingenuity of those who recreate these odours. In terms of breadth of smell, neroli oil – which is taken from the blossom of a bitter orange – has floral, citrus, fresh, and sweet odours, with notes of mint and caraway. Similarly, and yet dissimilarly, jasmine’s odour families are broken down into sweet, floral, fresh, and fruity, and – jarringly – intensely fecal.

The ingenuity of flavourists is exemplified by lily of the valley. The woodland, bell-shaped flowers are known for their evocative smell, but all parts of the plant are poisonous. Despite this, French company Dior synthetically recreated the lily of the valley smell in its Diorissimo perfume in 1956 using hydroxycitronellal, which is described by the Good Scents Company as having ‘a sweet floral odour with citrus and melon undertones’.

Cyanide smells like almonds, but you might not want to eat it.

Of course, as Dr Ellwood noted, synthetic flavours can only ever get so close to the real thing – an imperfect facsimile. However, the mere fact that chemists have recreated deer musk, lily of the valley, and the prized ambergris from sperm whales to create the fragrances we love is almost as extraordinary as the smells themselves.

‘Fragrance,’ he said, ‘will always be the confluence of the artistry of the perfumer and the chemist.

Register for our free upcoming SCI Talk on the Chemistry behind Beauty & Personal Care Products.