Organic – an organic essential oil is produced from plants grown without the use of chemicals like fertilizers or sprays.
Certified Organic – same description as above but is authorized/certified by the FDA here in the USA, or an organization like Ecocert Canada, in Canada.
Chemotypes – plants of the same species that are chemically different but otherwise indistinguishable resulting in different therapeutic properties.
Wild Crafted – essential oils that have been extracted from wild grown plants.
Selected Farming – where only specific plants are grown on a particular farm.
Fractionated – essential oils that have had part of their undesirable chemical composition removed. For example the terpenes which make bergamot photo-toxic and non-volatile are removed to create bergamot FCF.
Quenching – is a process of adding a chemical to a whole oil to help prevent unwanted side-effects like a skin irritation, for example adding d-limonene to lemongrass. This process is mainly used in the perfume industry. In aromatherapy using whole oils is very important because each essential oil has a unique chemical combination that affects the body’s chemistry.
Distillation - The most common method for extracting essential oils is by steam distillation. You get only the volatile and water insoluble parts of a plant using this method.
Expression - A method for extracting essential oils by pressure. This is used when the oil is very plentiful and easily obtained. Citrus oils are extracted using this method.
Extract- A substance made by extracting a part of a raw material, often by using a solvent such as ethanol or water. Extracts may be sold as tinctures or in powder form.
The aromatic principles of many spices, nuts, herbs, fruits, etc., and some flowers, are marketed as extracts. Among the best known of true extracts are; almond, cinnamon, cloves, ginger, lemon, nutmeg, orange, peppermint, pistachio, rose, spearmint, vanilla, violet, and wintergreen.
Solvent extraction - A method for extracting essential oils that is used when the oils would be damaged or destroyed if they used expression or distillation. Jasmine is an example of solvent extraction. A solvent (such as hexane or heptane) is used to pull, or dissolve the plant. The solvent is extracted for the creation of absolutes, concretes, and resinoids.
The majority of natural essences are obtained by extracting the essential oil from the blossoms, fruit, roots, etc., or the whole plants, through four techniques:
-Expression (see description above)
-Absorption; which is generally accomplished by steeping the substance in alcohol. Vanilla beans are often done this way.
-Maceration; tearing/shearing that is used to create smaller bits/pieces of the whole. Peppermint extract is made this way.
-Distillation, which is used with maceration, but in most cases this requires expert chemical knowledge and the erection of pricey stills.
The distinctive flavors of nearly all fruits are desirable adjuncts to many food preparations, but only a few are practical sources of sufficiently concentrated flavor extract. The most important among those that lend themselves to "pure" extract manufacture include lemons, oranges, and vanilla beans.
What is the difference between the herbal oils obtained by expression, solvent extraction, steam distillation or other methods? The overall content of oils in some herbs are not sufficient to make efficient the use of a press. On the other hand, steam distillation works only for volatile (essential) oils and may inactivate some temperature sensitive bioactive nutrients, important for the biological action.
Extraction with organic solvent is frequently utilized for the manufacturing of food additives and flavors from herbs. Obviously, direct oil extraction is preferable to organic solvents for skin care products.