Essential oils have been used in soap making for cleansing purposes for hundreds of years. An essential oil is a concentrated liquid containing volatile aroma compounds obtained from plants. They have a long tradition of being used in soaps. The word lavender comes from the Roman word "lavare" - to wash.
When you decide to use essential oils you should know basic information about the essential oil and how to use it safely. Knowing basic information about essential oils used especially in soaps will enable you to use essential oil safely and more efficiently in soaps producing results that are stable, therapeutic and aromatically long lasting.
Basic information that one should know are:
- Latin Binomial name of the essential oil - The name indicates the specific plant that the eo came from and the part of the plant used in the making of the essential oil. So for example, the bitter orange tree yields essential oil from the various parts of the plant, producing oil that is therapeutically as well as aromatically different. Thus essential oil made from the peel of the bitter orange has the common name Bergamot and the Latin name Bergamia Risso. while the leaves yield a different essential oil, Pettigrain (Latin name - Citrus Aurantifolia. Though both oils came from the same plant, yet they have totally different properties.
This is an important concept to understand since totally different chemical compositions will give one essential oil with the same common name a totally different therapeutic effect from another essential oil with the same common name. One such clear example of this exists in the Lavender essential oil family.
Lavandula Augustofolia officinales is true lavender, with a high ester content and a sweet aroma. It is grown in high altitudes in France. When we think of traditional aromatherapy applications for lavender oil, this is the oil that is used. This is also the highest priced lavender oil.
Conversely, Lavandula Latifolia (Spike Lavender)) grows at lower altitudes and has a strong camphor note but is cheaper and more widely used in soaps. Although it has some of the therapeutic benefits that true lavender has, it has more camphor and less ester.
With that said - all Lavenders have therapeutic qualities, just in varying degrees. The properties in Lavender essential oil makes it:
- Variation Used - Lavandula Intermedia (Lavandin) is a cross between true Lavender and Spike Lavender. It has many variations and is commonly used by soap makers as Super, Grosso and Abrialis. Lavandin is sterile much like the cross between a horse and a donkey - which produces a sterile mule. But Lavandin is stronger than its parents, more abundant and cheaper than its parents (true lavender and spike) - but the scent is not stable because it is a blend. And it does not have the true relaxing qualities of true lavender and therefore acts as a stimulant. Many folks who use this kind of lavender in their soaps do not realize that the finished product has a stimulating effect rather than a relaxing one. It is for this reason that one should do detailed research before using essential oils in applications or have your essential oils blended by a certified aromatherapist.
- Region that the oil came from - Oil grown in one region of the world may have a different aroma than those grown in other parts of the world. So any good supplier should divulge this information. There are many reasons for this some of which are the types of soil the plant grows in and other factors such as weather conditions and method of extraction. Some kinds of chemical extraction of the oil leaves residue in the oil that can be detected by an experienced nose.
- Flash point of the essential oil - The flash point of a volatile liquid is the lowest temperature at which it can vaporize to form an ignitable mixture in air (taken from Wikipedia). The flash point is especially helpful in soapmaking because knowing the flash point will help you determine several things: 1. whether to use a blend instead of a single note, 2. at what point in mixing the soap to add the essential oil and 3. whether to use the oil at all.
The flash point of Lavender is around 150F and if it is added to a soap mixture at trace it is very likely that the aroma will last if the mixture tracing is under 150F. To help that somewhat low flash point you could blend it with a essential oil with a higher flash point such as Geranium or Vetiver.
(Flash points and essential oils are a lengthy topic and will be discussed in more detail in another article)