Scent Synonyms: Extraction Method
From Plant to Bottle
Scent Synonyms is a series of articles looking at what names you’ll find listed on the bottle of your aromatic extract bottles and what they all mean. Before creating a fragrance, you should understand what different types of aromatic extracts you can use, and some of the subtle differences between them.
If you are an aromatherapist, you might be familiar with these names, but it’s always worthwhile making sure that something is what it says it is—and what to look out for, in case it is not.
Over the last five weeks, we’ve looked at three closely related names in our series of Scent Synonyms: Common Names, Botanical Names, and INCI Names. In the last two weeks, we’ve looked at Country of Origin and Type of Extract. Our final article in this series is Extraction Method.
Extraction Method: From Plant to Bottle
Last week, we looked at how the type of extract—essential oil, absolute, CO2 extract—might affect the scent of the extract.Closely related to that is the extraction method; what happens from plant to bottle, closely influences the final outcome (type of extract).
So, what are the main types of extracts that a botanical perfumer uses? Let’s take a look at the three that we discussed last week, in addition to a couple of other interesting additions:
Essential Oils: Steam distilled, water distilled, or a combo distillation (water and steam) (but see below for Expression as well). Sometimes an essential oil might be double distilled (distilled twice) or co-distilled (with another plant species). Plant material (leaves, flowers, twigs, orseeds) is placed in a huge vat where it is heated up. The essential oil molecules, from the plant material, “escape” and evaporate into steam which is forced along a pipe. The pipe passes through acold water vat and, as the steam cools, the essential oil molecules turn into a liquid – the essential oil. Essential oil molecules will either “sink” or “float” on the water, which means that they can easily be separated from the water to be used as an essential oil. Essential oils are not the exact chemical composition of the plant from which they were distilled, using this process. The number of factors will determine how closely an essential oil’s chemical components will match the original plant’s chemical components including the method of distillation, the length of the distillation process (some plants take longer than others to distill), and the degree of heat used in the process.
Expression: Expression extraction is a method that is used to extract citrus essential oils. You will notice that essential oils in citrus fruits are located in the rind of the fruit and consequently it is possible to squeeze out the juice (or the essential oil). Essential oils obtained by expression may contain some chemical contaminants because of the chemicals used to spray fruit trees (unless they are grown organically). Expressed essential oils are composed chemically the same as when they existed in the plant; there is little to no heat used in the process and you will therefore hear the term “cold expression” used in conjunction with the extraction of citrus essential oils. They will also contain natural waxes and other non-soluble components. Essential oils obtained via cold expression are collected by centrifugation.
CO2 Extracts: Carbon dioxide extraction involves using carbon dioxide at both high pressure and low temperatures to extract essential oils from the plants. Essential oils produced through carbon dioxide extraction and
distillation differ in chemical composition. You will notice that the aroma of carbon dioxide extracted “essential oil” is slightly different from that of distilled essential oil. Carbon dioxide extraction of “essential oil” is said to be more “pure” than the distillation of essential oils and closer to the original oil in the plant; there is no trace of carbon dioxide in the final product.
Absolutes: Concretes are prepared from plant material by the use of a hydrocarbon solvent to produce a waxy, solid substance that is widely used in the perfumery industry; absolutes are prepared from concrete by
alcohol extraction and are again of much use to the perfumery industry.
Tincture (Alcohol-based): Artisan perfumers use the tincture method to extract the scent of a plant that can’t be extracted by other methods or to use as an extending “note” in botanical perfumes. Plant material is placed in 190 proof alcohol and left to “tincture” for weeks to months at a time until the “right” scent is extracted (which is deemed “right” by the perfumer for what they are creating). Sometimes, a double or triple tincture is needed. I used this method for my Audrey on Air perfume.
Oil Infusion: An oil infusion of plants is often used by aromatherapists for therapeutic purposes. it is a lot more difficult for a scent extraction (depending on the plant in question). Jojoba (Simmondsia chinensis) is the preferred medium for perfumery work. Oil infusions are only suitable for oil-based perfumes, as they do not mix with alcohol-based perfumes.
Let’s take a quick look at some plants that you might used for each of the above described methods. Bear in mind that some of these are interchangeable between different types of extracts.
Plants for Different Types of Extracts
Essential Oil: Lavender (Lavandula angustifolia), mint (Mentha spp.)
Expression: Lemon (Citrus limon), lime (Citrus aurantifolia), sweet orange (Citrus sinensis)
CO2 Extract: Ambrette seed (Abelmoschus moschatus)
Absolute: Carrot (Daucus carota)
Tincture: Mandarin (Citrus reticulata)
This was the final article in the Scent Synonyms series and I hope that you’ve found it useful! VIP All Access subscribers will soon have access to an exclusive chart that will help them assess and summarize all of the information we’ve talked about and act as a great cheat sheet for comparing bottle label information (and more).
If you have enjoyed these helpful articles, you might be interested in a deeper dive into the business side of aromatics (where I expand on the information given in these articles, along with other business subjects). Although specifically related to aromatherapy, you might find our Certificate in Business of Aromatherapy useful when you are addressing the business side of your fragrance formulations. Alternatively, I offer an Aromatherapy Product Compliance Mentorship, which can also be used for natural fragrance products.
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Reader Action Point: Which extraction method were you not familiar with before reading this article?
“It is common sense to take a method and try it. If it fails, admit it frankly and try another. But above all, try something.”
Franklin D. Roosevelt (1882-1945), 32nd President of the United States
Great info here.