The quality and purity of essential oils are important to aromatherapists, who want a wholly natural product that duplicates the aromatic profile of the living plant source. Many lovers of essential oils are intimidated by the marketing hype, aggressive advertising and slick packaging that too often accompany the oils to the marketplace.
Despite attempts by leading aromatherapists and their organizations, no clearly defined and universally accepted and applied standard for the quality and purity of essential oils exists. Unless a company is distilling its own essential oils or working directly with growers and distillers, its oils probably come from one or more of the few U.S. importers of essential oils. These companies are reputable and provide good quality products, but most of their oils are sold to large fragrance and perfume manufactures, who demand oils that are consistent and unchanging from lot to lot (industrial quality). If the manufacturer of a popular cologne or perfume needs to make more product, the ingredients for the newest batch need to smell exactly the same as those used for the batch produced three months ago. Suppliers are adept at "enhancing" the chemical makeup of essential oils with other natural and synthesized fragrances to create a consistent product. Such manufacturers can supply the essential oils preferred by discriminating aromatherapists, but the buyer needs to communicate a realistic quality standard to the supplier -- and confirm that quality standard upon receipt.
An essential oil that is guaranteed by the manufacturer to be 100% pure and natural would seem ideal. But unless this guarantee is defined and put into contract form, it doesn't assure anything. The 100% pure and natural designation should be accompanied by the standard Latin and common name for the plant, indicating that the product was distilled exclusively from the plant source and not cut or altered by the addition of other natural or synthetic ingredients. Other factors to check for are acceptable extraction techniques, and storage conditions. The supplier should be aware of the standard proposed by the buyer and be held to them.
Results of Gas Chromatograph (GC) test and/or Gas Chromatograph with Mass Spectroscopy (GC/MS) test should accompany the lot of essential oil. A GC test produces a linear graph which charts the presence and distribution of the volatile components of an essential oil. A GC with accompanying MS identifies the individual components, along with their relative percentages. Although these scientific tests simplify the determination of essential oil quality, they can't replace the qualified essential oil or aromatherapy specialist who can evaluate the physical properties and action of the essential oil and its aroma. The evaluator should be aware of the acceptable color and viscosity range of the oil as well the characteristics and duration of the topnote, middlenote and dry-out aroma as it volatilizes over a fairly standard period of time.
These standards are intuitive, unique and highly specialized. When used along with the technical, scientific approach, they make possible an effective and reliable quality assessment of essential oils