Working with perfumery is an art. As with any art, the artist must learn its tools and techniques to eventually hope to master it. If you want to learn how to paint, you must learn about color theory, perspective, brush and paint quality, and a host of other subjects. Understanding and working with perfumery is no less complex, especially if you want to do it well. Often, however, I have run into people learning perfumery who seem to dismiss the most basic of tools they need to learn: botanical knowledge.
Let me re-enact here a not uncommon conversation between me and another fellow from a perfumery forum. Let’s call him ‘Joe.’
Me: “Perfumery is amazing. What drove you to study the craft?”
Joe: “I want to copy well known perfumes!”
Me: “OK, that’s nice… Any other particular interests that draw you to perfumery?”
Joe: “I want to make Cool Water perfume, and some of the Creed perfumes so I can sell them!”
By that point my interest in the conversation has mostly waned. Not because of Joe’s interest in copying some well-known perfumes (though selling them is a whole other matter I will not get into here), since it is one of the various great ways to learn perfumery, but because Joe’s interest in what goes behind the creation of such perfumes is really non-important. If I said to Joe that Cool Water contains Lemon, Cedarwood, Eucalyptus, Lavender among other botanicals, as well as a host of aroma-chemicals, Joe would most likely ask me the quantities and exact formula, and not really WHY these materials are in the mix. That is like wanting to build a house yet having no knowledge of architecture.
Don’t get me wrong. When I came into perfumery, I was seeking to recreate a well-known and discontinued vintage perfume for my mother. But I had worked with aromatherapy for decades and had always been fascinated by the actual botanical nature of the oils. Perfumery was, really, only a natural segue for me. I also learned a lot from gas chromatography of some high-class perfumes, not so much to perfectly recreate them, but to learn how the master perfumer had put it all together. That, to me, is fascinating. In fact, I always recommend on this site that people start learning by following the formulas available in Louis Appel’s book.
But regardless of how we approach perfumery, none of it is above the true nature behind it: the botanicals.
It’s all about Memories
The starting point for me when it came to perfumery and scent in general was beauty. If we dig deeply into human nature and ask ourselves why perfumery came to exist, one of the most obvious answers is: to make beauty last. This is why statues, carvings, photographs, movies, books, paintings and other expressive arts came to be.
Have you ever said to yourself, “I am so perfectly happy in this moment; I wish it would last forever”? The same concept is applied to perfumery. Imagine yourself walking through a flower meadow in mid-summer. You smell some delicate wild flowers, mown hay baking in the sun, clover growing around your feet, ripening fruits from nearby trees, honey bees collecting pollen, all rolled into a balmy breeze that caresses your face. I am sure I may have just conjured up some scents for you! Perfumery is a way for a perfumer to recreate such beauty and make it last, one that you can then beckon at any time with only a spritz or two of the perfume. How often have you talked to someone who mentions a specific perfume reminds them of a special time in their lives? It is no surprise that perfumery has been dubbed by some as ‘memories in a bottle.’
All those nature scents conjuring up so many beautiful memories stem from various botanical sources. Knowing more about those sources helps take a perfumer from ordinary to master. Why does a rose smell the way it does? And how does the scent of a red rose differ from a white rose, and why? Why do Lilies of the Valley have such sharp, sweet smell? What makes that happen? Tulips and Hydrangeas can smell green and cortex, while Jasmine sweet, balsamic and fermented. Bee Balm smells almost intoxicatingly strong, while Lavender smells floral and herbal.
This is where I say: Know Your Botanicals.
Scent Molecules in Flowers
By knowing what you’re working with, you can recreate, enhance and extend your perfume materials. Let’s take Lavender as an example. A lot goes into a Lavender perfume to make the Lavender scent actually appealing, by enhancing the actual oil. To quote W.A. Poucher: “Lavender Oil alone is entirely without value in toilet soaps and it is only by very skillful blending that its delightful perfume is fully developed.” 
In my Useful Links page, I recommend several books on perfumery, some of which I consider a must in every perfumer apprentice library. While some books on perfumery are laden with chemistry jargon, enough to make our brains spin, others are full of amazing information about plant material, plant origins and their chemistry. Learning about the botanicals you hope to recreate or use in your formulas is something I highly recommend. The more you know about a botanical, the easier it will be for you to include it in your formula, and to learn your perfumery materials. I often recommend people create soliflore formulas to learn their botanicals. A soliflore is a perfume based on one flower. A Rose perfume, for example, is a soliflore.
If you asked me what makes a Rose smell like a Rose, immediately off the top of my head I can say Geraniol, Citronellol, Nerol, Eugenol and Phenylethyl Alcohol (as 2-Phenylethanol). This list is by no means exhaustive, but they are among the primary materials found in Rose flowers. If you do some research, you can find gas chromatography analysis of Rose flowers with a very long list of chemicals contained in the scent. A perfume based on the scent of Roses goes from there. After much trial-and-error, which took me a few years, I finally managed to create a Rose perfume I am delighted with, containing 40 different aroma-chemicals and essential oils in it. And I learned much about roses in the process.
Once you learn about specific botanicals and what molecules are behind their scent, you will also learn to more easily relate to your perfumery materials. A great book, which contains the chemical makeup of most common essential oils, is Essential Oil Safety, by Robert Tisserand. In this book you can quickly find what top constituents are in various essential oils. When deciding that you may want to work with aroma-chemicals in your formula to emulate specific botanicals, without actually using the specific essential oils, this is of great help.
Let’s discuss Jasmine. This is a flower scent most sought after in perfumery. It will not take long in your practice to quickly learn that one of the main constituents in the scent of Jasmine is Benzyl Acetate. Any perfume that claims to contain Jasmine in it will contain Benzyl Acetate. This aroma-chemical features pretty much in most floral compositions. Among other constituents found in Jasmine are Benzyl Benzoate, Linalool, Indole, Eugenol and Jasmolactone. If you wanted to recreate Jasmine, these would be on your list. However, knowing these aroma-chemicals are to be found in the scent of Jasmine can help you more easily work with them in other formulas. You could create a floral perfume in which you include Benzyl Acetate, Jasmolactone and Indole and in the perfume’s description of the various components you’d list Jasmine, without a single drop of Jasmine oil ever being in your formula. Of course, some more expensive perfumes will contain a certain amount of real Jasmine oil, but for the most part the oil would be extended using some of the above aroma-chemicals.
Lavender is always another favorite. Some of the most important constituents in Lavender oil are Linalool and Linalyl Acetate, with others such as camphor and Borneol in lesser quantities. All Lavender oils will have these chemicals in them, but depending on where the oil comes from and its form, the quantities will vary. Lavender Absolute, for example, also has Coumarin and Geranyl Acetate in it. Knowing this, if you wanted to add a hint of Lavender to your formula without using the actual oil, which may add too much of a camphorous note, you’d use some aroma-chemicals like Linalool, Linalyl Acetate, Citronellyl Acetate, Terpinyl Acetate, and call it Lavender in your perfume description. Lavender Oil is also enhanced by these aroma-chemicals, and other chemicals and oils like Patchouli and Coumarin, to round out the Lavender’s sharp and comphorous edges.
You can see then that by knowing the molecular makeup of a botanical, you can most effectively recreate it or enhance it. This is important, because as I mentioned above, if you use a material like Lavender in your perfume, you will definitely want to enhance the oil. And if you wanted to create a Soliflore perfume, such knowledge would be invaluable.
Another reason to learn about your botanicals is when you want to use some essential oils which are not affordable, or are heavily protected. Rosewood Oil is one such case. The tree was affected by over harvesting and because it is now protected, the oil is hard to come by and rather expensive. Rosewood Oil is almost 90% Linalool, alongside Alpha Terpineol in smaller quantities. If you have both in your formula, you can list Rosewood (or Bois de Rose) without having used Rosewood oil at all. You can also use this knowledge to recreate Rosewood oil. Eventually you will find yourself in a garden, smelling a flower and immediately going, “I smell Geraniol!” And you won’t be able to smell cloves without smelling Eugenol.
The journey of perfumery is one of study and discovery, and it is never better than when discovering what makes a botanical smell the way it does, and being able to recreate your own memory of these by using your newly acquired knowledge.
 W.A. Poucher, Perfumes, Cosmetics and Soaps: The Raw Materials of Perfumery Volume 1, P.222