Not all plants give essential oils. Today, about 10% of listed plant species are classified as aromatic plants that can produce an essential oil. Thus there are major producing plant families:
conifers such as firs (Abies), pines (Pinus) or cedars (Cedrus), are commonly used. The needles, buds and bark of firs and pines are distilled, as well as the cones of cedars.
Apiaceae (formerly umbelliferae), constitute a very widespread family of plants. Rich in essential oils, they are often used as herbs: dill (Anethum),anise (Anisum), fennel (Foeniculum), cumin (Cuminum), coriander (Coriandrum)…
Asteraceae, formerly called “composite”, constitute the most important plant family. Its best-known aromatics are yarrow (Achillea), mugwort (Artemisia), but also wormwood (Artemisia absinthium), tarragon (Artemisia dracunculus), chamomile (Chamaemelum)…
Lamiaceae with the many therapeutic virtues contained in their essential oils and with antioxidant properties. It includes lavender (Lavandula), thymes (Thymus), basils (Basilicum).
Other families are also very useful in aromatherapy such as Betulaceae with birch (Betula), Cistaceae with cistus (Cistus), Cupressaceae with cypress (Cupressus), Ericaceae with wintergreen (Gaultheria), geraniaceae with geraniums (Pelargonium)…
By what process do we obtain an essential oil?
The highest quality ofessential oil is obtained without solvent, by the process of steam distillation. The latter crosses the tank containing plants and takes care of their aromatic molecules. Cooled in the coil, the steam condenses; the HE separates from the water to be collected in the essence. Carried out at low pressure, slow and prolonged distillation – or integral distillation – makes it possible to extract all of the components with therapeutic properties. To obtain one liter of EO, you need an average of 35 kg of plants; in the case of the fine lavender, more than 150 kg of flowers! Two other processes are also used: the expression which consists in pressing the part of the plant concerned to recover the essences (peel of citrus fruits) and the extraction by solvent during which the essences are dissolved in a volatile solvent (and not in water). A technique used in perfumery, not in therapy.
Read also :
Essential oils: how are they produced?
Aromatherapy, where does it come from?
Not all essential oils are created equal