Essential oil basics

A few days ago, I did a stocktake on my essential oil collection; it seems that, within the past 6 months, I have amassed more oils than I realise! (Now, how did I let that happen?! ?) Whilst going through the different bottles, it occurred to me I should probably share with you some of the things I’ve learned about essential oils. So here they are!

What are essential oils?

In short, the term essential oil refers to the volatile liquid extracted from parts of a plant, such as the flowers, fruits, seeds, leaves, stems, bark, roots. [Volatile means the oil evaporates quickly at room temperature.] The “oils” are usually extracted by distillation (by steam or water); some are extracted by expression, which is also known as the cold-pressing method) – citrus oils (oils taken from the peel or rinds of fruits like orange, lemon or lime) are examples of expressed oil. Essential oil are incredibly concentrated – it takes about 2.5kg of peppermint leaves just to make 10g of essential oil (according to this)! As such, they bear strongly the aroma of the plant.

If you’ve ever shopped for essential oils you’ll notice that their prices vary a lot: while oils like lavender, bergamot, peppermint are very reasonably priced, others like sandalwood, neroli, rose absolute and jasmine are incredibly expensive. The reasons for this are:

  1. the amount of plant needed to extract the oil – a number of sources I’ve read have quoted that it takes over 10,000 rose petals to make a 5ml bottle of rose essential oil
  2. the rarity and/or scarcity of the plant – for example, the sandalwood tree has been given a “vulnerable” status due to excessive felling; the roots of this tree are most valuable because they yield the best-quality oil, which means whole trees have to be felled in order to get this oil.

Some people call essential oils "precious oils" - I can definitely see why! [image credit: https://flic.kr/p/4HnznH, by Fadi F , reproduced under CC BY-ND 2.0
Some people call essential oils “precious oils” – I can definitely see why! [image credit: https://flic.kr/p/4HnznH, by Fadi F, reproduced under CC BY-ND 2.0]

Essential oils vs. fragrance (or perfume) oils

The main difference is that essential oils are derived wholly from a plant, while the majority of fragrance (or perfume) oils are synthetic creations, made to imitate the aroma of a particular fruit or flower. You may have also come across something called “blended essential oils” – they’re often bottled up like essential oils and are placed on the same counter. Basically these oils contain some essential oil, but they are often so heavily diluted with carrier oil (for example, sweet almond oil) that they no longer offer the full qualities of the essential oils they contain.

It’s also important to remember: not every fruit yields an essential oil! While many fruits have a nice scent, it doesn’t mean they are available in essential oil form. For example, it is not possible to extract essential oils out of strawberry, coconut, peach or mango; citrus fruits are the only fruits whose peel can yield essential oils. (AromaWeb has a list of the parts of plants that produce essential oils.)

Uses of essential oils in body and skincare

From aromatherapy to natural insect repellent, there are many uses of essential oils. In body and skincare, they are used mainly for their scent, for the sensation they bring (e.g. a warming or cooling sensations), and for the properties and health benefits with which they are often associated (e.g. anti-bacterial, anti-septic, anti-microbial properties; as reliefs for cramps, motion sickness, headaches; to help improve concentration). Given the health-benefit aspect of essential oils is such a big topic in itself, it won’t be possible for me to cover everything in this post; if you’d like to find out more about it, please check out the links in my “Additional reading” section.

Here, I should point out another very important point: essential oils should never be used undiluted on the skin, since they may irritate your skin or an allergic reaction. Take great care when choosing and using essential oils in your products: For example, some citrus oils are phototoxic, which means they cause skin irritation if applied on skin that is exposed to sunlight; likewise, other oils are unsuitable for use with babies, young children, or during pregnancy. (For more on essential oil safety, see “Additional reading”.)

In body and skincare, the accepted safe usage rate of essential oils generally seems to range between 0.5% to 3% (that’s the percentage of the total weight of the product). The rate varies depending on the oils you’re using, the product you’re making (e.g. use a lower % if it’s in a cream you rub into your skin; in a wash-off product like a soap you can use a little bit more), and the user your product is for (e.g. the % has to be a lot lower if the product is for children). Again, always do your research before using essential oils in your products, and remember, less is more! If in doubt, consult a medical professional or qualified aromatherapist for advice.

Essential oil scent groupings and notes

There are many ways to categorise essential oils: by the part of the plant they’re from, by their chemical properties, by the health benefits with which they are associated. Another way – one which I find most useful personally when I first started dabbling in DIY body and skincare – is to group them according to their scent.

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What I’ve compiled here is a table outlining the main scent groupings and some examples of essential oils in each of those groups. Also included are the “fragrance notes” – which are to do with how fast the scent evaporates. Scents that are quickest to evaporate are detected by our nose most quickly – they are given the name “top note”; “base notes” are used to describe scents that are slowest to evaporate and therefore stick around the longest.

Scent category Examples (Note: Top/Middle/Base)
Citrus bergamot (T/M), grapefruit (T), lemon (T), lemongrass (T), lime (T), sweet orange (T)
Floral chamomile (M), jasmine (B), lavender (T/M), neroli (M) , rose (M), rose geranium (M), ylang-ylang (M/B)
Herbaceous basil (T/M), rosemary (M), thyme (T/M), sage (T)
Minty peppermint (T), spearmint (T)
Camphorous
(“medicinal”)
camphor (T), eucalyptus (T), peppermint (T), rosemary (M), tea tree (T/M)
Spicy anise (T), black pepper (M), cardamom (M), cinnamon (T), ginger (T/M), nutmeg (M)
Woody cedarwood (B), cypress (M), juniper berry (M), pine (M), sandalwood (B)
Earthy oakmoss (B), patchouli (B)
Sweet oriental spice benzoin (B), vanilla (B)

Many products use not just one but a combination of oils (and usually one from each “note” category) to achieve a particular scent and sensation. For example, a balm made with lemon, lavender, rosemary and cedarwood essential oils can produce a sweet and woody scent with a cooling sensation.

Use your nose!

One thing I found when I first started reading about essential oils was that it can be tricky to “understand” an oil without having smelt it. So get yourself down to your local health store (or any shop that sells essential oils and provide testers) and start smelling! Remember, though, do not inhale deeply straight from the bottle – these oils are so concentrated that inhaling too much may cause you to feel unwell! Ask the owner/staff in the shop for a tissue or a scent strip.

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I hope you’ve found this post useful! And now, I’d like to finish with a game suggestion: Next time you come across a fragrant product you like, see if you can identify the scents and find out what, if any, essential oils have been used. Then take a look at its list of ingredients and see if you have managed to correctly identify the oils!

Additional reading

  • This webpage from Dummies.com provides a good introduction to essential oils.
  • This webpage from the National Association of Holistic Aromatherapy (USA) explains the methods by which essential oils are extracted.
  • The Aromatherapy Bible website by Danièle Ryman has a fantastic A-Z of plants, with lots of information on the properties and benefits of each one.
  • AromaWeb has published some very useful information about essential oils including oil profiles, oil safety and uses of oils.
  • If you’re interested in the chemistry behind some popular essential oils, check out the blog by Susan Barclay-Nichols.

Featured image credit: https://flic.kr/p/eaFRRJ (cropped), by Anita Gould, reproduced under CC BY-NC 2.0

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