Right now, in a lab somewhere, someone is testing a scent combination for the 491st time. Months have been spent systematically adjusting ratios of woodsy to floral, looking for balance. Or rather smelling for balance: For perfumers, evaluation happens way back in the nose, via millions of olfactory receptors [source: Fox].
You may not know any perfumers by name, but you definitely know their work. Chanel's No. 5 (1921) was the brainchild of Ernest Beaux, perfumer to the Russian czar and pioneer of perfume synthetics [source: Chanel]. Jacques Guerlain created Shalimar (1925). Calvin Klein's Obsession (1985) was Jean Guichard. Sophia Grojsman made Eternity (1988). Dior's J'Adore (1999) was Calice Becker [source: Fragrantica].
Each of these perfumers blended essential oils, the aromatic building blocks of a perfume, and experimented with different ingredients and proportions until he found himself inhaling a scent that evoked something -- a feeling, a sense, a mood -- and "unfolded" perfectly from first whiff to final, fading waft.
This is the most visible aspect of the perfumery trade and certainly the most glamorous. But what perfumers actually create are simply scents, and those scents have endless applications. The "sensual jasmine" of a perfume. The "calm vanilla" of a body wash. The "clean and fresh" of a laundry detergent, "meditative lavender" of an aromatherapy candle or "fresh and soothing" white tea of a Westin hotel lobby [sources: Starwood, Palmer].
Scent formats are countless. Perfumers – "noses" in industry speak -- are not. Perfumery is an exclusive line of work, to put it mildly. It's also somewhat mysterious, a unique blend of art and science that seeks to define, in olfactory terms, the undefinable.
The Art and Science of Scent
The sense of smell, or olfaction, varies dramatically from one person to the next [source: Monell Chemical Senses Center]. What we can and cannot smell is often genetic, scientists are finding [source: Howgego]. Some people are simply born with the ability to smell more substances, and with greater sensitivity, than others.
Perfumers are some of those people. A "good nose" is critical to the work, as is curiosity [source: Academic Invest]. Great perfumers are constantly experimenting, combining essential oils in surprising ways as they search for some elusive aroma, an olfactory experience that achieves the desired emotion or effect when someone applies it.
That's the art. The science is molecular chemistry, the critical platform on which this creative experimenting and innovating rests.
Scents are particles of matter, comprised of molecules. When those molecules attach to any of the scent receptors in the human nose, the brain interprets them as smells [source: Stone]. The chemical properties of scent molecules determine not only how they smell but also how they act and interact, evident in the behavior of a perfume's three scent components: top notes, middle notes and base notes [source: Perfume.org]:
- The top notes are quickest to the nose and quickest to dissipate, because their molecules are small and volatile.
- The middle notes reach the nose second and last long enough to overlap with the third component, the base notes.
- The base notes last the longest and create the overall sense of a perfume. (See How Perfume Works to learn more about notes).
Perfumers use their knowledge of these molecular properties to design a scent that "unfolds," or evolves over time. And when they set out to create a scent, they start at the bottom, with the base notes.
Creating the Scent of a Sense
Creating a perfume is a process of trial and error that can take weeks, months or years. Perfumer Ruth Mastenbroek spent three years creating her self-named signature fragrance (2010). Christopher Brosius spent five years creating his award-winning Snow (2000), which smells like snow [source: Gray]. But they were creating for their own lines; when creating for a client, a month or so is more common [source: Bradley].
A perfumer typically begins with an olfactory goal in mind, and the process starts with selecting essential oils for the base notes [source: Perfumer's Apprentice]. Notes are individual scents. When various notes are combined, they form a new scent called an accord. A base accord, middle accord and top accord make up a perfume.
To create a base accord, a drop of each selected essential oil is applied to the end of a separate test strip (or "scent strip"), a long, thin piece of blotter paper with room on one end for notes. Holding those test strips together, the perfumer smells the resulting accord. If it works, voila. Base accord.
Far more likely, the experiments start.
Proportions of the essential oils may be adjusted incrementally, repeating the test-strip process for each new ratio, making comparisons and taking notes. A third or fourth essential oil may be added. One of the original essential oils may be removed. And with each new combination comes another round of test strips, ratios, comparisons and notes [source: Perfumer's Apprentice].
When the perfumer is holding an array of scent strips that emits the perfect base accord, the process starts anew for the middle notes, eventually resulting in the middle accord. Once the middle accord is perfected, that set of strips is paired with the strips of the base accord, and experimenting begins again, this time making adjustments based on the interaction between the base and middle accords. And then again with top notes – creating the top accord, joining that accord with the middle and base accords, and experimenting until the combination of the three, which will be the perfume, is just right [source: Perfumer's Apprentice].
Achieving this result can take hundreds of trials [source: Academic Invest]. But for those with the dedication to break into the world of commercial perfumery – there are apparently more working astronauts than working perfumers -- it's a labor of love [source: BBC].
A Rare Breed of Nose
Some artistic souls with amazing noses stumble into the career, but that's rare. Many start their careers working in perfume stores or as lab technicians for perfume manufacturers [sources: Bradley, College for TN]. Others are chemists who discover a love of scent and follow their noses [sources: Bradley, Givaudan].
A degree in chemistry is required, as are years of additional, specialized training in cosmetic science and the specifics of perfumery [source: Academic Invest]. Lots of colleges, universities and private organizations offer perfumery courses, and some offer certificates in the art, but specialized degrees are harder to come by and often require studying at a dedicated perfume school. Those are relatively few, and the most prestigious ones are highly selective: The Givaudan Perfumery School in Paris accepts about 2 percent of its applicants [source: Hume]. For comparison, Harvard University accepts about 6 percent [source: U.S. News & World Report].
Perfume schools offer courses in topics like scent formulation, applications of natural vs. synthetic essential oils, olfactory evaluation and physical-chemical analysis. Trainees learn the scents and qualities of hundreds of natural and synthetic chemicals, developing their olfactory memories [sources: College for TN, ISIPCA]. They spend years as apprentices to master perfumers [source: College for TN].
Students typically also study marketing and business subjects, because perfumery isn't all test strips [source: ISIPCA]. It requires an understanding of consumers, the retail industry, quality control and business management: what people want in a perfume, how to analyze industry trends, how to tell the techs who prepared test batch 3 they messed up the formula [source: Academic Invest].
A formula that took 491 trials to perfect. But that's par for the course. Perfumers are a patient folk.
Right now, in a lab somewhere, someone is adjusting the ratio of musk to vanilla to orange for the 61st time, remembering a decades-old citrus grove, wondering what an oakmoss note might do for the accord ...
Author's Note: How Perfumers Work
Explaining how a perfumer arrives at "subtly dark and sensual" is kind of like explaining how van Gogh achieved "turbulent and lonely" – you don't. Creative processes seldom translate. So I settled here for the concrete: ingredients, ratios, training. Perfumers are artists, and each has his or her unique approach to the work. To get a real feel for the art of perfumery, you probably need to get a set of essential oils and some scent strips and have at it.
- Academic Invest. "How to Become a Perfumer: Career Path Guide." (Dec. 18, 2014) http://www.academicinvest.com/science-careers/chemistry-careers/how-to-become-a-perfumer
- The American Society of Perfumers. "What is a perfumer?" (Dec. 18, 2014) http://www.perfumers.org/about-1/
- BBC. "Perfume: Bottling the Memory." (Jan. 10, 2015) http://www.bbc.co.uk/programmes/b012cnns
- Bradley, Georgie. "How do I become ... a perfumer." The Guardian. Dec. 12, 2013. (Dec. 18, 2014) http://www.theguardian.com/money/2013/dec/12/how-become-perfumer
- Chanel. "No. 5 Culture Chanel." (Jan. 11, 2015) http://5-culture.chanel.com/en/une_histoire_damour/
- College for TN. "Perfumer – What They Do." (Jan. 10, 2015) https://secure.collegefortn.org/Career_Planning/Career_Profile/Career_Profile.aspx?id=XAP2FPAXkUX0ekOXAP2FPAXh9dafRmBVILWAXAP3DPAXXAP3DPAX
- Fox, Kate. "The Smell Report: The human sense of smell." Social Issues Research Center. (Jan. 4, 2015) http://www.sirc.org/publik/smell_human.html
- Fragrantica Perfumes Magazine. (Jan. 11, 2015) http://www.fragrantica.com/
- Givaudan. "Perfumery School." (Dec. 18, 2014) http://www.givaudan.com/fragrances/perfumery-school
- Gray, Geoffrey. "The Invisible Scent." New York Magazine. April 24, 2011. (Dec. 18, 2014) http://nymag.com/news/features/perfumer-christopher-brosius-2011-5/
- Gross, Liza. "A Genetic Basis for Hypersensitivity to "Sweaty" Odors in Humans." PLOS – Biology. Oct. 30, 2007. (Jan. 4, 2015) http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0050298
- Howgego, Josh. "Sense for scents traced down to genes." Nature. Aug. 1, 2013. (Jan. 10, 2015) http://www.nature.com/news/sense-for-scents-traced-down-to-genes-1.13493
- Hume, Marion. "Making Scents of It." Time magazine. April 1, 2009. (Jan. 10, 2015) http://content.time.com/time/specials/packages/article/0,28804,1882059_1882224_1882012,00.html
- ISIPCA. "School and Graduate Programs Overview." (Jan. 10, 2015) https://www.isipca.fr/en/node/175
- Keville, Kathy and Mindy Green. "Aromatherapy: A Complete Guide to the Healing Art." Ten Speed Press. 2012. p. 14. (Accessed Jan. 4, 2015) Available from: http://books.google.com/books?id=G7wd8N_jNJcC&printsec=frontcover#v=onepage&q=grasse&f=false
- Milojevic, Marina. "Musk." Fragrantica Perfumes Magazine. (Jan. 11, 2015) http://www.fragrantica.com/notes/Musk-4.html
- Monell Chemical Senses Center. "Variability in olfactory receptors affects human odor perception." ScienceDaily. Dec. 8, 2013. (Jan. 11, 2015) http://www.sciencedaily.com/releases/2013/12/131208133402.htm
- Palmer, Alun. "20 fascinating facts about our sense of smell." The Mirror. June 22, 2013. (Jan. 4, 2015) http://www.mirror.co.uk/lifestyle/health/20-fascinating-facts-sense-smell-1977351
- Perfume.org. "What are top notes, heart notes and base notes? Fragrance notes explained." (Jan. 10, 2015) http://www.perfume.org/all-about-perfume/what-are-top-notes-heart-notes-and-base-notes-fragrance-notes-explained
- Perfumer's Apprentice. "Advanced Blending Using Modern Key Accords." (Dec. 18, 2014) https://shop.perfumersapprentice.com/t-PerfumersCornerAdvanced.aspx
- Perfumer's Apprentice. "Quick Start Beginner's Blending." (Dec. 18, 2014) https://shop.perfumersapprentice.com/t-PerfumersCornerQuick.aspx
- Perfumers World. "Stephen V. Dowthwaite – Profile." 2012. (Jan. 10, 2015) http://www.perfumersworld.com/page.php?id=28
- Starwood Hotels and Resorts. "Westin Hotels & Resorts Unveils New Nature-Inspired Public Space Concept." Aug. 14, 2012. (Jan. 11, 2015) http://development.starwoodhotels.com/news/3/454-westin_hotels_resorts_unveils_new_nature-inspired_public_space_concept
- Stone, Alex. "Smell Turns Up in Unexpected Places." The New York Times. Oct. 13, 2014. (Jan. 10, 2015) http://www.nytimes.com/2014/10/14/science/smell-turns-up-in-unexpected-places.html?_r=1
- U.S. News & World Report. "Top 100 – Lowest Acceptance Rates." (Jan. 10, 2015) http://colleges.usnews.rankingsandreviews.com/best-colleges/rankings/lowest-acceptance-rate
- Williams, Kate. "So you think you want my job? – Perfumer." Cosmopolitan. February 2012. (Jan. 10, 2015) http://www.icatsaromaeducation.com/wp-content/uploads/2011/01/2012-Cos-Job-Article.pdf