Updated: May 28, 2020
It’s time to talk science: perfume compounds, otherwise known as the RAW MATERIALS.
Both of these terms are important to know, as they are used interchangeably. They are not soluble in water, but they are fully dispersible in alcohol and carrier oils, such as jojoba.
Raw materials consist of essential oils, absolutes, natural isolates and synthetic molecules.
But what are the differences between these four types of raw materials?
1. Essential oils AND absolutes are naturally derived from the aromatic part of the plant and are processed to be a pure aroma substance. (if you don;t know what an absolute is keep reading!)
BUT WHAT PART OF THE PLANT IS USED?
The oil is only extracted from the aromatic part of the plant and that varies, the first one may surprise you!
Did you know…? Of the tens of thousands of plant species found on earth, only 300-500 are used in perfumery or aromatherapy. The other thousands are either too difficult to extract or do not have an aroma to extract.
NOW. Let’s dive into the extraction process for these naturals, and then return to the other raw materials. The extraction process is the method that we use to take the oil from the aromatic part of the plant.
There are five ways to do this, each with its own purpose.
1. Steam distillation
The most common method. The harvested flowers or plant parts are placed in a large industrial vat over steam. As the steam goes through the flowers, it travels through an enclosed pipe to another tank where it collects. Since water and oil do not mix, they separate with ease. The oil is taken with a tap and the water is drained from the bottom. But fear not dear fans of recycling – this precious water is not discarded!
The ‘floral water’ is a by-product of the distillation process and is repurposed as a hydrosol that can be used as a face mist or to consume when refined to food grade. Where do you think the rose water you see on supermarket shelves comes from?!
Consider making your own lavender water, for example, to help calm a cranky infant (since essential oils are too strong for babies).
Many farms then use the mulch that is left over for the process as a compost for the next crop, so absolutely nothing goes to waste.
Watch the video about the world's best Ylang-Ylang and the new distillation method designed by my friend!
Not to be confused with cold pressing which is used for oils like olive, grape seed etc.
Citrus fruit oils like bergamot, lime and sweet orange are made using expression. The peels are pressed with thousands of tiny needles to the point that the oil is expressed. Then, the oil is separated from the water by centrifuge or further pressure.
Cocktail party trivia: Rose and most other oils are not really ‘oils’, they are aromatic isolates that we call an oil, because they are not soluble in water. Citrus oils however are actually oils.
3. Solvent extraction
This method is very practical for delicate flowers, such as jasmine, narcissus and frangipani. This extraction is used rather than steam distillation because either the heat would destroy the fragrance, or the flower does not give up her scent so easily. Like all elegant, classy ladies!
Sometimes this method is used AS WELL AS steam distillation for roses and lavender for example, since it gives a different aroma profile than the distilled oil, so you can have 2 scent profiles from the same flower adding a more complex, rounder accord to your perfume.
For this method, the plant is dissolved in a solvent like hexane, which pulls the oils from the plant. The oils, waxes and fats are washed with warm alcohol, which is removed by a vacuum afterwards, leaving us with a pure aromatic oil.
Absolutes are generally less expensive than their distilled compatriots because less material is required.
This is an old-fashioned technique that is rarely used nowadays. This traditional method was pioneered in 17th century France. It was used for certain flowers that do not give up their scent easily, such as lilies or tuberose. The method is to soak the petals in animal fat until the fat is completely saturated with the fragrance. The fat is then washed with alcohol to capture the perfume, and the alcohol evaporates to leave the fragrance compound. Fresh flowers are replaced in the fat over and over again until the fat is ‘full of fragrance’ hence this is a very labour intensive method and the reason it is rarely used any more.
Robertet is the only large manufacturer that I know of that still uses this method today for the precious Tuberose flower.
Fun fact: Did you know that Tuberose is related to the humble daffodil?
5. Carbon Dioxide extraction
Or Co2 extraction, which uses pressurized CO2 to pull the desired phytochemicals from the plant. At certain temperatures, the carbon dioxide acts like a solvent, but does not have the dangers that solvents bring with them. With this method, the CO2 quickly and completely evaporates without requiring heat. The final essential oil has an scent that is closer to the plant’s living aroma than with steam-distilled oils, but these are oils are more costly.
Most of these oils are pretty expensive. But why?
Because so much of the source plant/flowers are needed to produce such a small quantity of the oils.
Here are only a few examples to prove my point: to make one kilogram of Neroli oil, you need 1000 kilograms of flowers; to make one kilogram of Rose oil, you need roughly 700 kg of flowers.
Time to return to our raw materials. All of the above-mentioned processes render us with essential oils or absolutes. But remember, there are four kinds of raw materials: essential oils, absolutes, natural isolates and synthetic molecules.
You will hear the word absolute quite often in perfumery. The difference between absolutes and essential oils is the process of getting the oil. Absolutes are always obtained through solvent extraction or enfleurage.
It is also important to know about natural isolates. If you are extracting a single molecule, it is a natural isolate.
If you are extracting an entire compound, it is an essential oil. Natural isolates are more powerful, and therefore costlier, but the benefit is that they are more stable. Take a rose, for example. The entire compound (aka, the “smell”) consists of three natural isolates: 2-phenylethanol, geraniol and citronellol.
Synthetic molecules are another perfume compound found in aromatherapy. They are completely man-made (hence the word synthetic!). Typical synthetics include chocolate, caramel, leather, gooseberry, etc.
Tip du jour: Want to give your sweetheart three dozen roses for Valentine’s day but you can’t make it to the florists? Substitute the fresh roses with a single drop of Rose essential oil... Because that’s how many roses it takes to make just one drop!
Think of how many details we have learned within that one tip! A rose has a compound smell made up of three different natural isolates. The way to get the rose essential oil is through a variety of extraction techniques, in this case steam distillation or solvent extraction. The only thing that this oil can mix with are carrier oils, never water.