Essential Oils and absolutes are usually sold for individual use in very small bottles. They are commonly sold in 5ml, 10ml and 15ml (1/2 ounce) sizes. For more expensive oils, it is common to find them in sold in sizes starting at 2ml and 1 dram sizes.
Although essential oils do not become rancid, they can deteriorate and lose their therapeutic benefit over time. Oils such as the citrus oils will oxidize and begin to lose their aroma and therapeutic properties. Not all oils lose their value. Some oils such as patchouli and sandalwood can improve.
To avoid deterioration and protect the aromatic and therapeutic properties, your oils should be ideally kept in amber or cobalt blue bottles. Dark glass such as amber or cobalt helps to keep out sunlight which can hasten deterioration. Be leery of purchasing any oils sold in clear glass bottles. Run if you find an essential oil sold in a plastic bottle.
When purchasing oils, be skeptical of oils that are bottled in clear glass or have a rubber dropper incorporated into its screw-top cap. Droppers with rubber bulbs should not be kept with the essential oil bottle as the highly concentrated oil can turn the rubber bulb into gum. Most essential oils are sold in bottles that contain an “orifice reducer.” An orifice reducer is a small, usually clear insert inside the bottle opening that acts as a dropper. You simply tip the bottle and you can dispense the oil drop by drop.
