Picking up a bottle of perfume or cologne at a department store, have you ever wondered what’s actually in it? I’ve asked a bunch of people about this, and answers range from essential oils, to chemicals, to answers closer to the truth. Well, I’ve made a list that’s about as exhaustive as possible, though do let me know if I’ve missed something. Here’s the list:
Solvents
Usually ethanol but occasionally oil, this makes up most of what’s in the bottle – usually between 80 and 95 percent. It costs almost nothing to produce, but is necessary to dissolve and preserve the other materials, as well as to dilute them and prevent overly-strong odours and potential fabric staining.
Synthetic molecules
These are individual molecules that are created in laboratories from raw materials such as petroleum, lanolin, and pine wood. Most fragrances are primarily made of synthetic materials, owing to their stability, consistency between batches, low cost, flexibility, and ease of use in production. Natural materials contain hundreds of types of scent molecule, and so are more complex to combine, while synthetics are lab-made and are composed of just one molecule each. It’s kind of like the difference between painting and découpage, the former allowing for complete control but more work than the latter.
Essential oils
Less common than synthetic molecules because they cost more and are harder to work with. They are extracted from plants by steam distillation, which involves passing steam through fresh or dried plant matter to extract their volatile scent compounds. Essential oils can also be extracted through cold pressing, which is essentially just squeezing the plant matter and then waiting until the oil rises to the top of the juice. The term ‘essential oils’ may conjure images of bad health advice and not-quite-pyramid-schemes, but fear not, perfumers by and large don’t care in the slightest for theories of these oils’ supposed healing abilities or mystical qualities. It’s an industry that approaches fragrant art with a very scientific attitude, so you can rest assured that essential oils are only being used in the pursuit of olfactory pleasure.
Absolutes
Due to their high cost, these are rare in most fragrances you’ll find at a department store, but will often be present in pricier niche perfumes. They’re extracted using solvent extraction, which involves mixing plant material in vats of a solvent (such as hexane), allowing the solvent to draw out the aroma compounds in the plant material. It also draws out substances such as pigments and waxes. At this point, the solvent is removed using vacuum processing, leaving a waxy substance known as a concrete. The concrete is then stirred into alcohol, which the aromatic molecules dissolve into, leaving the other substances behind. The alcohol can then be evaporated off in a low-pressure chamber, leaving the absolute.
Concretes
As mentioned above, these are a stage in the absolute extraction process. Because the wax won’t dissolve in alcohol, these are useless for standard perfumery, though they are sometimes used in soap making and solid perfumes.
Resins
These don’t require any extraction, as they occur naturally in the form of sap oozing out of tree trunks. Examples are myrrh, frankincense, and benzoin. For the sake of consistency between perfume batches, they are often refined to remove impurities, but other than this do not require any processing.
Tinctures
These are made by soaking a natural material (e.g. vanilla beans) in alcohol for a period of weeks, months, or longer. They aren’t used much because other methods of scent extraction are faster and more thorough. However, they still have a place in the independent perfumer’s palette because they are more subtle than essential oils and have a slightly different smell. Some can also act as fixatives, helping make top and middle notes last a little longer. Within this category is an interesting material called ambergris, an exceedingly rare material which for hundreds of years was found in lumps on beaches without any evidence as to what it was or where it came from.
Carbon dioxide extractions
Some natural materials lose their smell when exposed to high temperatures, which means that steam distillation isn’t possible. CO2 extraction is rather more technically complex than the other extraction methods, so I think it deserves its own post. Like absolutes, the cost of these mean they are not commonly used.
Extraits
This is probably the most labour-intensive way to extract oils from flowers and is only used on the most delicate blossoms. It works using a method called enfleurage, where flowers are placed gently on glass trays covered in animal fat for around one to three days, after which the fat is mixed and the flowers are replaced with fresh ones. This is done many times before the fat becomes saturated with the oil. It is then mixed with alcohol until the oil leaves the fat and infuses in the alcohol, at which point the fat is removed. This is more of a traditional method of extraction, and is so costly that basically all perfumes using extraits will mention the fact to drive customer interest and sales.
Preservatives & other functional materials
Preservatives and UV filters are often present in fragrances to protect against incorrect storage, such as keeping the bottle in the bathroom.
In the end, what matters most is that the perfumer handling the materials is an expert. Quality ingredients alone won’t create a masterpiece, just as expensive paints in the hands of a child rarely yield positive results. I’ll write more in the future about the techniques that perfumers use when creating fragrances, but hopefully I’ve satisfied your olfactory curiosity for the moment.
