PLANT EXTRACTS AND WHOLE-PLANT PARTS
As natural beauty formulators, we turn exclusively to plants for our product ingredients, carefully considering the wide spectrum of aromatic and medicinal properties unique to each one. In some instances, we may find it helpful to use the entire plant part. For example, in our Fresh Anti-inflammatory and Brightening Facial Mask (see page 177), we use the full strawberry as an ingredient. In other recipes we may use an extract of a plant to better deliver the specific constituents needed for a product’s efficacy.
Your knowledge about when to use an extract (and what method of extraction is most suitable) or the whole plant part will come into focus as you learn the art and science of blending. First, let’s take a look at the role of extracts and the history of their use in our world of plant-based beauty.
Plant-based beauty literally means that all the ingredients we use to formulate our recipes come directly from plants. Plants are composed of incredibly complex and amazingly rich molecular compounds that humans have learned to interact with for millennia.
The evolution and development of herbal (and modern) medicine grew out of the ways in which we interacted with plants and our observations of how they behaved within their environment. For example, the indigenous people of Australia, while living amongst the tea trees, noticed that when leaves fell into nearby waters, the waters, when bathed in, could heal wounds. This discovery made them curious and led them to understand that there was something in the tea tree plant that was somehow preventing the growth of microbes and bacteria. They wondered, if something in the tea tree prevents bacteria from growing in still waters, how can we use the tea tree to help us avoid infections?1
This question is at the root of what inspired early humans to figure out ways to use plants for medicine. Their interactions and experiments with plants demonstrated that certain preparations of plant material worked more effectively than others for a wide variety of conditions, and soon the practice of making medicine was in full swing.
Extraction is the process of obtaining a plant’s medicinal (that is, therapeutic) constituents through various methods that are designed to get these unique components out of the plant. It is important to note that different methods of extraction yield different kinds of medicinal materials, and these varying types of materials are better suited for different beauty applications.
For example, carrot seeds, when expeller-pressed, produce a lipid-rich seed oil that is used as an emollient for skin creams, salves, and serums.2 But when this identical seed is processed through a different method of extraction, like steam distillation, the lipid-rich components remain within the plant material, while the volatile aromatic molecules are released, vaporized, and collected in the resulting essential oil, which can be used for both physical and psychological/emotional applications.
Extractions are possible from a spectrum of plant materials, including roots, seeds, leaves, resins, wood, fruits, citrus peels, and flowers.
To help bring the concept of plant extracts into focus, so you have a better grasp of their unique characteristics for purposes of skincare formulating, we have broken down the most common approaches into nine categories of extraction methods:
1. Steam distillation: A process of extracting aromatic components from plant materials using an apparatus called a “still.” Various plant materials, which can come from leaves, flowers, fruits, roots, seeds, wood, bark, or resins, are collected and prepared (meaning the material is either dried, finely chopped, or ground) and then loaded into the part of the still called the retort, which, depending on the size of the still, can look like a large vat. Steam is then introduced, or pumped, through an adjacent pipe that feeds into the retort, passing through the plant material and releasing its aromatic molecules. Once the aromatic molecules are released from the plant material and make contact with the steam, they vaporize and molecularly bond with the steam, flowing through a pipe that is fastened to the top of the retort. This pipe then curves and coils and passes through a cooling area called a condenser, which transforms the steam back into its water-like state and guides it out of the still, from which it flows into a collection vessel. The essential oil, since it is not dissolvable in water, floats on top of the water (the remaining water without the essential oil is known as hydrosol) and is then siphoned off and collected separately. Since steam distillation uses only water, steam, and gentle heat, it is one of the cleanest and purest methods to extract aromatic molecules.
2. Cold expression: A method of extracting the aromatic molecules from the peels of various citrus fruits, like lemon, lime, yuzu, grapefruit, orange, and mandarin. In this process, the peel is removed from the fruit and then pressed under high pressure, without heat, to squeeze out and collect the essential oils. Cold expression is also considered a pure and clean method of extraction, resulting in an essential oil.
3. Expeller-pressing: A popular approach for extracting the lipids (that is, the fatty molecules) from nuts, seeds, and whole fruits, like avocado, sea buckthorn, and olive. This process involves two steps: first the seeds, nuts, and fruits are sorted and cleaned, and then they are put in a large pressing apparatus that squeezes all the oils out of the raw material. Although a reputable processor will not add heat to the pressing process, it is important to note that the actual pressing motion of the machinery may cause enough friction to generate heat naturally, which can alter some of the fatty molecules present in the yield.
Be on alert that some processors may wash the nuts and seeds in high heat and/or solvent solutions to loosen the shells and break down the seed coat to make the pressing process yield higher quantities. To avoid any trace residues of solvents in your beauty products, stay away from vegetable oils that are processed with either solvents or high heat, and choose only cold-pressed oils for beauty formulating.
4. Solvent extraction: A process that uses a petrochemical, usually hexane, to dissolve and absorb the aromatic molecules from plant material. Unfortunately, this chemical process may consequently dull the potentially therapeutic energetic activities. The aromatic substance a solvent extraction yields is called an “absolute.” This method of extraction is most often used to extract the aromatic molecules from very delicate flowers and plant materials that are not capable of withstanding the heat from the steam-distillation process. Hexane can also pull out waxes and pigments from the plant material, giving the resulting absolute a richer color and more viscous texture. Perfumers tend to use absolutes more readily than aromatherapists do because absolutes can help fix the aromatic palette, so the odor profile of the fragrance does not change over time. Solvents are also often used because they make the extraction process less labor-intensive and more cost-effective.
Beauty Tip! 
We recommend selecting authentic essential oils over absolutes for your beauty recipes. Absolutes can often have trace residues of phenyl ethyl alcohol and hexane, which may absorb into the skin and disrupt the body’s energetic balance.3
5. CO2 supercritical extraction: Also known as hypercritical extraction, this is a process that uses liquid CO2 as a solvent to help dissolve the chemical components from aromatic and medicinal plant material for use as an ingredient. CO2 extractions may be used to scent a product (aromatic), or they can be used to extract particular therapeutic components like rosemary extract or sea buckthorn oil.
You may find CO2 extracts sold alongside essential oils as organic and authentic aromatic materials. We love working with them, especially when we find one that fits our aromatic profile. Unlike absolutes, CO2 extracts have no concerning residues and can provide a complex scent experience—we encourage you to experiment with a few.
6. Enfleurage: A technique that uses fats, either vegetable or animal, to extract only the aromatic components of the plant material. In this process, which is usually reserved for extremely delicate flower blooms, the plant material is freshly picked and immediately placed on a layer of softened fat. The fat draws out the aromatic molecules and becomes infused with the scent. The plant material is removed, and what is left is a solid mix of scent-infused fat, which can be further diluted using alcohol or other vegetable oils.
7. Infusion: An extraction method in which the plant material (seeds, resins, roots, etc.) is submerged in what is called a “menstruum”—a fluid that helps dissolve particular components from the plant materials. These particular fluids are used primarily to dissolve the components in the plant material that cannot be removed by water. For example, a menstruum could be vegetable glycerin, vinegar, alcohol, or vegetable oil. The process is as follows: The plant material is usually dried and ground and then submerged in a menstruum and left alone for 2 weeks to 2 months. During this soaking period, the menstruum dissolves the active chemical components. Once the soaking period ends, the plant material is strained, and the end product—known as an infusion, tincture, or glycerite—is the menstruum fully charged with the active chemical components of the plant.
If you decide to use an extract that you don’t make yourself, make sure you know the process by which the extracts are made since the menstruum itself (that is, alcohol or olive oil) can carry with it particular skin concerns and actions. You should always ask the company from which you purchased the extract if the extract contains any added antioxidants or preservatives.
If you don’t want to make your own extracts and instead choose to purchase them from a verified source, make sure you ask how the infusions, tinctures, or glycerites were extracted so you can understand how all the components will combine in your recipe.
8. Decoction: A method in which plant material is soaked in hot water. Extractions produced by this process, also known as “teas,” are prized beauty ingredients known for their gentle therapeutic properties. The soaking process allows plant materials to release their more water-soluble chemical components. These kinds of teas can be used in beauty recipes like facial masks, gels, and cleansers to enhance the recipe’s healing and beautifying properties; all you need to do is blend the tea with the water or hydrosol part of the recipe.
9. Extraction of flower essences: The extraction of nonaromatic essences that contain only the vibrational and energetic components of the plant materials. These essences are extracted via solar or lunar energy in water. The plant material is placed gently on the surface of the water and allowed to float. It is then left in the sunlight or the moonlight for a period of time; this process allows its vibrational and energetic components to vibrationally imprint and be memorized by the water. The plant material is removed and the water remains charged with its energetic properties. That water is then portioned off and preserved with alcohol, glycerin, or vinegar.