Perfume creation is both an art and science, where at Scent Journer each ingredient is selected with mindfulness and intention to enhance your sensory experience. Understanding the differences between essential oils, absolutes, and CO2 extracts is essential to appreciating the complexity and quality of our perfumes. Let's delve into the world of these aromatic treasures and explore their unique characteristics.

When presented with little amber bottles like these, we are quick to assume they are essential oils. Essential oils have taken the world by storm, touted for their almost miraculous myriad of health benefits and aromatic pleasures. However, not everything presented in these amber bottles is essential oils. Other natural and synthetic oils such as fragrance oils, absolutes, and CO2 extracts are out there on the market and each type of oil has distinct characteristics, uses, and methods of extraction. Understanding the differences between these different types of oils is crucial for making informed choices in aromatherapy, perfumery, and other applications. Let’s clarify these differences and help you understand which type of oil is best suited for your needs.

Natural Oils

Natural (fragrance) oils are defined as oils containing isolated naturally occurring fragrance compounds from a more complex scent, derived from a botanical or nature-based source. We will cover a few natural oils commonly sold and used in the fragrance industry today. 

What is an essential oil? 

Essential oils are concentrated oils extracted from various parts of plants, including leaves, flowers, stems, roots, and bark. A mix of volatile components that vary depending on the plant material, these oils capture the essence of the plant’s fragrance and beneficial properties, and the term ‘essential’ refers to the fact that the oil contains the "essence" of the plant's scent - the characteristic fragrance of the plant from which it is derived. These are popularly used for aromatherapy, which is a holistic healing treatment that uses natural plant extracts to promote health and well-being. Some popular essential oils include lavender, peppermint, eucalyptus, and tea tree. 

Aside from Aromatherapy, essential oils are also popularly used as natural disinfectants and household cleaners as is the case for lemon and tea tree essential oils due to their antibacterial, antiviral, and antifungal properties. 

How are essential oils made? 

Essential oils are obtained through various extraction methods, including steam distillation, cold pressing, and solvent extraction. Each method is chosen based on the nature of the plant and how the oil will be used. The basic concept of all essential oils is that it is an extract - a botanical ingredient is placed in a solvent, causing parts of the plant material to dissolve, allowing it to infuse into the solvent. 

1. Steam Distillation
   
   
   

   The most popular method to extract and isolate essential oils from plants. The steam is injected and passes through the plant material, vaporizing its volatile compounds, which eventually condense into a liquid mixture of the volatile compounds and water. As water and oil do not mix, the essential oils will float on top of the water or sink depending on their density, and the oil alone is collected as the final plant extract. However, oils derived from steam distillation vary in quality depending on the temperatures, pressures, and length of time applied for the process as the molecular composition of both the plant matter and the essential oil is changed due to the temperature applied
   
   

2. Cold Press Extraction:

   The preferred method for citrus peels, this method involves mechanically piercing the rind, to release the essential oil sacs that sit below the rind. The citrus fruit is then squeezed to release the juices and oils together, which are then filtered and centrifuged (spun at high speeds) separating the oil from the juice.
   
   

3. Water Distillation:

   Delicate flowers such as roses and orange blossoms would clump together when introduced to steam in the distillation process, thus fragile plant material is submerged directly in pure boiling water instead. The water protects the extracted oil from overheating. The condensed liquids cool down and the oil and water separate from each other. The remaining water, which can sometimes be fragrant, is referred to by several names including hydrolate, hydrosol, herbal water, essential water, floral water, or herbal distillate.

What are Concretes?

Concretes are highly concentrated aromatic substances derived from plant materials through solvent extraction. They are solid or semi-solid masses composed of essential oils, waxes, resins, and other plant constituents. Concretes are known for their rich, robust fragrances and are a vital intermediate product in the production of absolutes, another highly concentrated form of aromatic extracts.

How are concretes made? 

Concretes are produced using food-grade solvents like hexane and ethanol to isolate essential oils from plant material via a process called solvent extraction. It is best used for plant materials with low essential oil yields, and resinous, or delicate aromatics as this method does not use excessive heat, steam, or water. 

Ingredients are submerged in a solvent mixture, which dissolves the aromatic compounds of the plant and releases them into the liquid. The liquid is then evaporated under controlled conditions to produce a mix of wax and oil which is the concrete. 

Concretes not typically used directly in liquid perfumes due to their waxy consistency but serve as a crucial intermediate in the fragrance industry as they are instead processed into  high quality absolutes. However, concretes are quite popular for use in solid perfumes. Next, lets look at absolutes, what they are and how they are made form concretes.

What are Absolutes?

Similar to essential oils, absolutes are highly concentrated, aromatic, oil-based mixtures. However, absolutes are much more concentrated than essential oils thus they must be used with greater dilution, and they are produced using different methods. 

Absolutes are commonly used in perfumery, cosmetics, and aromatherapy. 

How are absolutes made?

As mentioned earlier, absolutes are produced from concretes which are produced using solvent extraction. 

Using the concrete produced from solvent extraction, it is dissolved in alcohol (usually ethnaol), in which the aromatic compounds will infuse into, leaving behind the wax. This insoluble wax is filtered off and the alcohol is distilled off via vacuum distillation, leaving behind the fragrant, concentrated mixture known as an absolute. 

Absolutes typically smell more like the original plant than essential oils because they have not been heated. Many plants can be used to create both essential oils and absolutes, but some ingredients are only available in absolute form because of their nature.

One of the oldest methods of extraction, enfleurage was the traditional way of making absolutes though it is no longer used as commonly today. Utilizing animal or vegetable fats which are initially odorless, botanical ingredients are either stirred into hot fats or left to sit on the cold solid fats till the scent has diffused into it, infusing the fats with the plant’s fragrance compounds. This fat can be used as it is or it could be soaked in alcohol to draw out the fragrant compounds, and thus produce an absolut of the botanical compound after evaporating off the alcohol. 

CO2 Extracts: How are they made?

As the name implies, CO2 extracts use CO2 extraction - using carbon dioxide in its liquid form to extract botanical oils. Following the same concept as steam distillation, liquid CO2 acts as a solvent to extract the plant’s volatile compounds before the CO2 is evaporated away, leaving behind just the oils. However, unlike steam distillation, using CO2 as a solvent allows for a lower temperature of extraction and an overall gentler process, thus CO2 extracts are closer in chemical composition to the original plant, as they contain a wider range of the plant’s constituents unaltered by the heat. Hence a higher quality of oils is extracted.

CO2 extracts are usually thicker than their essential oil counterparts with a stronger aroma than a distilled essential oil. CO2 extracts have been said to contain more plant constituents than the amount extracted from the same plant using steam distillation. Thus CO2 extracts produce a highly pure and potent product. 

CO2 extracts can be used in similar manners to essential oils and absolutes for aromatherapy, skin, or cleaning products and fragrances. Common CO2 extracts include pink pepper, and Sichuan pepper, however, most botanical matter that can withstand steam distillation can also undergo CO2 extraction as it is much gentler. CO2 extraction is however limited as it is still unable to produce extracts from high-moisture botanicals such as fresh fruits and vegetables. This is because the water in these fruits and vegetables can form ice or slush under supercritical conditions, causing blockages and inefficiencies. Thus CO2 extraction works best with dry materials such as dried peppers, wood, and spices. 

Synthetic Oils/Fragrances

Unlike natural oils like those mentioned above which are derived from their respective botanical matter, synthetic oils are compounds manufactured in laboratories and are not extracted from natural products. One benefit of synthetic oils is that they are able to mimic scents found in nature by synthesizing the specific fragrance molecule in the lab. This can be useful in creating scents originally derived from toxic plant matter and are often cheaper to produce in large quantities than using natural sources. 

Synthetic oils may also be favored over natural oils as synthetics can be tailored to give a stronger scent that lasts longer on the skin than what can be achieved with natural oils. One example of this is Cherry Blossom fragrances. However, these synthetics should not be named as essential oil since its not naturally extracted by steam distillation. 

Unsurprisingly, most novelty fragrances like pumpkin spice or birthday cake are produced synthetically in the lab as there is no natural source that contains a specific chemical compound that smells like birthday cake or a pumpkin spiced latte. Synthetics of common essential oil fragrances such as lavender and rose can also exist by synthesizing only the key aromatic compounds such as linalyl acetate and linalool for lavender, and geraniol and citronellol for rose fragrances. However, these synthetics are not believed to confer the same medicinal benefits that the essential oil versions confer through aroma therapy as synthetic oils are more focused on producing and replicating the desired scent as opposed to capturing the ‘essence’ of the botanical matter as is the case with natural oils. Thus synthetic oils are mostly used in cosmetics, fragrances, and various household fragrance products from candles to cleaning solutions.

Fragrance Oils

Though the term is frequently used as a blanket term for all oils that carry a fragrance including essential oils and others, fragrance oils refer to oils that can be made with a mixture of natural oils (including essential oils, CO2 abstracts, absolutes, etc) and synthetic oils or purely just synthetics. The oils are mixed to produce specific accords and combinations of aromas, which allows for greater freedom and creativity to produce fragrances with greater depth and scent profiles. 

While perfumes made of naturally derived ingredients do exist, the majority of them contain synthetic oils, especially fragrances that list musk, and non-citrus fruits as a note in their scent profiles. Animal-derived musks have been banned following increasing environmental awareness and animal conservation efforts, thus most musks on the market today are purely synthetic musks with unique scent profiles attributed to their distinct chemical structures. Meanwhile, noncitrus fruits such as watermelon, apple, strawberry, and pear are unable to be successfully distilled into their essential oil form, thus it is not possible to produce these scents naturally through the same methods as citrus fruits. 

It is important to note that if an oil writes ‘fragrance’ on the ingredient list, it is likely a synthetic fragrance oil or contains synthetic oils even if the fragrance itself is commonly found as a natural oil. 

Conclusion 

Whether it is used for aromatherapy, product fragrance, or perfumes, both natural and synthetic oils can be found in any product that carries a fragrance today. Versatile in their uses and applications, understanding the differences between these products is crucial to allow you to be a more conscious consumer and be more knowledgeable about how and what goes into your favourite fragrances.