Essential oils vary enormously in price and quality, depending on two main factors: the amount of oil found in the plant material and the integrity of the distillation process. The more oil glands present in the plant, the cheaper the oil, and vice versa. For example:
100kg lavender yields 3ltr essential oil
100kg rose petals yields ½ ltr essential oil
In order to benefit from the healing properties of the oils, it is vital to purchase them from a reputable supplier who takes care to ensure high standards. Before accepting a batch, a sample will have been tested, using gas chromatography, to see whether the characteristic ‘signature’ of the pure essential oil is evident. The word ‘natural’ on a bottle’s label does not always guarantee purity. It is sensible to check that the description states ‘pure essential oil’ and that the botanical name is included i.e. Lavendula angustifolia
Buy oils in small quantities as you need them, replacing them as required
The chemicals found in essential oils range from safe alcohols to esters, Aldehydes and substances like phenols, which are more toxic, but safe when used correctly. When you use your oils you dilute them for external application, but you must first ensure that they are stored properly. If you don’t, chemical changes may occur that mean they may be unsafe to use.
Essential oils last for a relatively long time, up to two years, if a few simple precautions are taken. In particular citrus oils such as orange and grapefruit may only be effectively used for up to six months then they will go cloudy through oxidation. On the other hand there are a few essential oils which improve with age, rather like some good wines. These are often the oils which originate from plants which have taken a long time to mature, e.g. sandalwood and frankincense.
Blended oils remain effective for up to three months if stored in a cool place such as a refrigerator.
They should always be bought in dark-coloured glass bottles with a stopper that automatically dispenses them a drop at a time.
Keep the lid firmly closed to prevent evaporation, and store them in a cool place out of direct sunlight and away from direct heat.
The citrus oils tend to go off more quickly than other oils, so it is a good idea to buy them in small quantities as you need them.
It is easy to tell if an oil has deteriorated: it will become cloudy and give off a distinctly unpleasant odour.
Essential oils rapidly break down if not properly stored. Their enemies are as follows:
- Keep essential oils out of sunlight.
- Never place essential oils near heaters, stoves, fireplaces, lit candles or other sources of heat.
- Keep them firmly capped and never leave the cap off a bottle for more than a few seconds.
- The bathroom is the worst place to store essential oils. Keep them in a cool, dry place and they should last for some time.