Essential oils aren't some rare and exotic tinctures from distant lands (Ok some of them are!). We have all encountered essential oils in our daily life; peel an orange and the spritz that is released from the the peel (and usually gets in your eye!) is it's essential oil. Step out into your garden and crush a sprig of Rosemary, Thyme or Mint in your hand and the sharp scent that coats your fingers is the essential oil. Essential oils are present in every plant (though some are more abundant in oils than others), not only do they give each plant its own distinctive scent and unique flavour but they also play a valuable part in its survival - attracting pollinating insects, protecting the plant from disease, repelling predators (think about companion planting) and helping healthy growth. Some even think that the essential oil is the very life force of the plant.
The oils are concentrated in different parts of the plant and depending on the level of oil glands or cells within the plant this impacts the amount of essential oil that is extracted from the plant. Take for instance Lavender which is abundant in essential oil; 100 kilos of Lavender yields around 3 litres of essential oil, while a pricey 100 kilos of delectable Rose Petals yields just 1/2 litre of essential oil. But as essential oils are a highly concentrated essence (around 70-100% more concentrated than fresh or dried plant material) only teeny amounts are needed.