Expert Advice: Be sure you are buying sustainable essential oils

Essential oils are expensive, and with good reason. It takes around 10,000 roses to produce 5ml – that's a whole teaspoon!

Rose essential oil is extracted through steam distillation. Large stills, traditionally made of copper, are filled with the roses and water. The still is then fired for an hour or so. The vapourised water and rose oil leaves the still, enters a condensing apparatus, and is then collected in a flask. This yields a very concentrated oil. Water condenses with oil and is then drained off and distilled again. The two collections, once combined, make the final rose essence, or Rose Otto essential oil.

Rose Otto is typically only used in aromatherapy. Rose Absolute is favoured in the perfume industry and is traditionally made using the enfleurage method, which involves animal fat or beeswax.

For consumers reluctant to use animal by-products, organic solvent extraction is now a commonly used technique for extracting this form of aromatic. The raw materials are submerged and agitated in a solution or bath that is capable of dissolving the desired aromatic compounds. The price remains as high as we are still dealing with vast quantities of handpicked ingredients to yield the oil.

Roses are grown annually and can be repeatedly harvested, but there are less fruitful plants that are more difficult to harvest, and it is critical that they are protected to ensure sustainability of the species. One such plant is Frankincense.

The oil is derived from the resin of the super hardy Boswellia tree (pictured), which typically grows in the dry, mountainous regions of India, Africa and the Middle East, often in places that are difficult to get to. Experts say that the tree should be cut no more than 12 times a year to keep them healthy. In the mountain regions of countries like Somalia this is difficult to monitor as the trees grow in areas with harsh climates, often plagued by poverty and conflict, and may be the only source of income for local people.

Thousands of tons of Frankincense are traded every year to be used by priests as incense, natural medicines and essential oils. It goes without saying that anyone sourcing Frankincense should be sure that it is being sourced sustainably. Frankincense trees aren't covered under the Convention on International Trade in Endangered Species (CITES), the global treaty that regulates cross border trade in plants and animals, although experts argue that Boswellia species meet the criteria for protection.  

In the case of Rosewood (pictured), CITES has put restrictions on the trade of all 300 species, in an attempt to clamp down on illegal logging of this timber. Having plundered the forests of Southeast Asia to virtual extinction, traffickers have turned to West Africa and Central America for the prized timber. The good news is that reputable suppliers of this essential oil will always sell it with a CITES certificate so you can trace the origin of the Rosewood oil you are using and be sure it is grown and harvested sustainably.

The situation is similar for Sandalwood, a vulnerable species, but one that is prized in perfumery for its heartwood and roots. As a result of uncontrolled harvesting in India, where it is highly valued for its use in perfumes, soaps, incense, cosmetics and medicines, it is increasingly being grown under governmental protection. India has imposed an export ban on Sandalwood and instigated conservation measures to protect this species in their country. Sandalwood is now mainly grown sustainably in plantations in Australia, so again you need to be sure where your Sandalwood oil is being sourced if you really care about sustainability.

However, there are cheerier stories. You may have heard of Vetiver in the context of perfumery. It has a wonderful woody, earthy base note, predominantly used in men's fragrances. Vetiver (pictured) is a tall grass. It can grow up to five feet, but more importantly the root structure can grow to a depth of 20 feet, which makes it fantastic at preventing soil erosion and promoting soil conservation. It is grown all over the world for a multiplicity of uses from basket weaving to Ayurvedic medicine, and as it can be planted and harvested in a two-year cycle, is a very sustainable product and one that provides tremendous support to agriculture practices and earnings around the world.

The simplest of extraction method is Expression, known to you and me as squeezing. It is largely used for citrus essential oils such as Mandarin, Grapefruit, Lemon, Lime. These oils tend to be cheaper and, as they typically dissipate quickly, are generally used as top notes. As we all know, these fruits grow sustainably and plentifully close to home.

So, remember, if you are offered cheap essential oils, they will be cheap for a reason. Check where your oils were sourced.

Kim Brookes is the founder of Perfino, an innovative natural scent jewellery brand that combines expertly blended, 100% natural, pure essential oils with jewellery.