Primer: Using Essential Oils

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Essential oils

Chances are you’ve used essential oils most of your life. These substances find their way into many common products, including mouthwashes, perfumes, soaps, household cleaners, and liniments.

You may also find these fragrant oils in their pure form in small, dark bottles lining your health-food store’s shelves. Many people use them as perfume, to scent massage oils, or for aromatherapy. And as the research continues on the chemicals found in plants, several essential oils have emerged as useful medicines.

What is an essential oil?

If you have ever used an essential oil, you may have been surprised by its con­sistency. Cooking oils are ­exactly that—oily. But most essential oils have a consistency more like water. The main difference between cooking oils and essential oils is how quickly they evaporate. Although both come from plant sources, this simple contrast makes a world of difference in how they are used.

The word essential refers to plant essences, volatile oils that provide a plant’s flavor and smell. Volatile means that these oils turn from a liquid to a gas (evaporate) very easily at room temperature or higher—this is how they travel to your nose. The “oily” oils, such as corn or peanut oil, are called fixed oils, which means they don’t evaporate, even at the relatively high temperatures necessary for cooking.

How we get them

Essential oils begin as tiny droplets contained in different plant parts such as leaves, stems, bark, flowers, roots, and fruits. Plants make these oils to protect themselves from insects or other invaders, or to attract pollinators like bees and butterflies. Different oils can come from different parts of the same plant. For example, a single bitter orange tree (Citrus aurantium) provides three different oils: neroli oil from the blossom, oil of bergamot from the fruit peel, and petitgrain from leaves and twigs. Some plants contain very few essential oils.

Essential oils are ­extracted using one of five methods: steam distillation, enfleurage, maceration, expression, or solvent extraction. Each of these processes breaks down a plant’s cells to release its oils.

Essential oils are highly concentrated: One acre of peppermint may produce a ton of dried leaves but only twelve pounds of essential oil, according to Herbs for Health adviser Steven Foster. Sometimes these oils can be 75 to 100 times more concentrated than the fresh herb, making them very potent.

How we use them

Essential oils are used in a variety of ways. In cooking, the flavors and aromas from spices and herbs come from their essential oils. The familiar paint thinner turpentine is an essential oil extracted from the southern pine (Pinus palustris), a tree in the pine family. Aromatherapy practitioners use essential oils for emotional and physical well-being. Often, herbs’ medicinal qualities can be traced to compounds in the oils.