In Jean Carles' classification of perfume notes according to volatility, he refers to heart notes as 'modifiers of base notes'. Using paper scent strips and a few fragrant materials, I measured the longevity of a few of the notes he mentions by the amount of time their characteristic scent lingered on the test strip.
Note:
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Jean Carles' Classification:
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Concentration:
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Tenacity on Scent Strip:
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Bergamot Italy
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Top
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1%
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30 mins
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Linalool
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Top
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5%
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2 hrs 20 mins
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Galbanum Turkey
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Heart
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1%
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6 hrs 30 mins
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Aldehyde C-12
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Heart
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9%
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8 hrs 20 mins
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Rose Absolute
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Heart
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1%
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18 hrs 30 mins
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Jasmine Absolute
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Heart
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1%
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2 days 4 hrs
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Vetiver India
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Base
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1%
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3 days 4 hrs
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Sandalwood Australian
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Base
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2%
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7 days 7 hrs
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Musk Ketone
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Base
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5%
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9 days 4 hrs
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Oakmoss Absolute
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Base
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50%
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Forever
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So my experimental evidence is more or less in agreement with the classifications provided by the perfumer's table. I do wonder to what extent the concentration of the notes that I tested affected their longevity on the paper (which is greater than the longevity on skin), particularly in the case of the oakmoss, which is still going strong today, about 2.5 weeks after I dabbed the strip with absolute. The power of the different notes varies not only from the standpoint of longevity, but also sillage/projection: the distance the scent emanates from the source. Projection tends to increase with increasing concentration for each note, but galbanum diluted to 1% is still quite clearly stronger than the Aldehyde C-12 diluted to 9%.
What follows is a brief description of the ten notes discussed above. Bergamot is a citrus note that also has a slightly bitter woody aspect. Its use in perfumery is both very traditional and very common. The perfume ingredient is obtained by pressing the peel of the bergamot fruit. Citruses are a canonical top note, and bergamot is no exception.
Linalool is a natural molecule found in many plants and flowers, but can also be synthesized. It is, like bergamot, very common, and has a light, clean floral scent, with a bit of green sweetness. It smells smooth. The molecular formula is C10H18O and the molecular weight is slightly over 150 g/mol.
Galbanum is an aromatic resin, a product of certain Persian plant species. Its scent is greengreengreen, a bit too bitter, cold, harsh, or something to be fresh, particularly in high concentrations. That said, I don't mean any of that in a negative way.
Aldehyde C-12 is, like most aldehydes, used to give a perfume more height or lift. To me, aldehydes smell bubbly -almost carbonated- and buoyant. Chemsitry-wise, aldehydes are molecules that contain a terminal carbonyl group, or a carbon atom double-bonded to an oxygen atom at the end of a chain. Like linalool, aldehydes are natural molecules that have been reproduced in a laboratory setting. Fatty, or aliphatic, aldehydes, the type that are generally used in perfumery, also contain a long chain of carbon atoms (generally 8-13) connected to the terminal carbonyl group. Some other aldehydes used in perfumery contain a ring-like structure of carbons, such as benzaldehyde (which smells like almonds) and contains what is called, in organic chemistry, a benzene ring. Aldehyde C-12's molecular formula is C12H24O, and it's molecular weight is a bit over 180 g/mol. Aldehyde C-12 has powdery ambery citrus nuances.
Rose Absolute... despite the fact that extracts of flowers don't smell quite like the flower itself, as one would experience it in real life, I will say that the absolute in my possession is very recognizably rose. And that said, there are many varieties of roses, each smelling somewhat differently. Some are spicy and dark, others pinker and fresher and lemon-y. Rose absolute is usually steam- or solvent-extracted from the flower (typical varieties being damascene and centifolia.
Jasmine, being a white flower, has an interesting scent. Petal-like and creamy, with undertones of indole (a sort of dirty smell that is also present in feces and decaying garbage). The absolute I used for this study comes from the jasmine grandiflorum varietal, but jasmine sambac is also widely used in perfumery. Jasmine absolute is extracted through a process called enfleurage, but there are synthetic jasmine-smelling substitutes available.
Vetiver is a type of grass native to India. It smells woody, smoky, green-grey- somewhere between fresh and musty.
Sandalwood is a traditional perfumery material that has a creamy, milky, and rich warm wood fragrance. The highest quality source of natural sandalwood is Mysore sandalwood in India, which is now protected from harvesting due to its being an endangered species. What is commonly used in perfumery now is Australian sandalwood, which smells similar, though rather harsher. Synthetic sandalwood molecules have also been developed.
Musk ketone is a nitro musk, created synthetically in the late 1800s and found to resemble Musk Tonquin 9 (a natural, highly pricy, and not quite cruelty-free material). Most nitro musks have been eliminated for health and environmental reasons (for more about the health effects of nitro musks...). It's formula is C14H18N2O5 and its molecular weight is about 290 g/mol. I'm going to assume that musk ketone isn't carcinogenic. given that it was fairly easy to get access to.
Oakmoss smells... well, mossy. In high concentration I find that it resembles molasses, while in lower concentration it smells rich, creamy, and earthy. A component of fragrances in the chypre genre (do read this article about the history of the chypre), it has been heavily restricted due to dermal sensitization issues. It is a species of lichen that grows usually on the trunks of oak trees in deciduous forests of the northern hemisphere, though it may also grow on other species of tree (in which case its odor is slightly different). The absolute can be obtained by solvent extraction or vacuum distillation.
Having written about each note under inspection more individually, there are a few last things I found should be mentioned. The first is that not all of the notes have a provided molecular weight. This is because natural materials, like absolutes and essential oils, contain many different molecules, as opposed to synthetics, which are single molecules created in a lab through a synthesis reaction designed to yield that individual molecule. For this reason, natural ingredients are often perceived as being more complex- after all, they have a more varied ingredient list.
However, for the molecular weights that were easily obtainable, we can see clearly that they increase with the experimental longevity I found- which fits the general rule that the lightest notes are the most volatile, and the heaviest the least volatile.
- Linalool photo stolen: Wikipedia
- Aldehyde C-12 photo stolen: Givaudan
- Musk keton photo stolen: Wikipedia
