Essential oils are liquid extracts of various potentially beneficial plants. They can be obtained from leaves, flowers, seeds, fruits, roots, bark, resin, wood and other parts of plants. Manufacturing processes can extract these compounds from these plants. Common extraction include Steam distillation, infusion, supercritical CO2 extraction and solvent extraction. Essential oils are widely used in the areas of chemical industry, pharmaceutical, industry cosmetic industry, and food industry. Essential oils often have a much stronger smell than the plants they come from and contain higher levels of active ingredients. This has to do with the amount of plant matter required to make essential oil.
A series of factors affect the quality of an essential oil including botanical origin, part of the plant used, climate and method of oil production. The quality of the essential oil may be compromised if any one of these factors is not considered carefully for that particular plant. When an essential oil is intended for clinical aromatherapy purposes, the specific botanical sourced and its quality become even more important; Gas chromatography (GC) and mass spectrometry (MS) can analyze the constituents in oils.
Heat ,oxygen, light and moisture may influence an oil's shelf life. Therefore, do not store Essential Oils in the bathroom, near a stove, on a window sill or other sunny area. You can store an oil in the refrigerator or freezer. This option is especially ideal for those who use their oils infrequently. If oils freeze or form crystals, simply allow them to naturally return to room temperature before using them.