During the age of enlightenment, scientific advances led the general population away from herbs and towards treatments such as antibiotics and pharmaceuticals. Recently, however, an unexpected shift back to herbs and essential oils has begun as more people in North America, Europe and Australia are consulting trained herbal professionals and using herbs and essential oils in their homes. Sales of herbal medicines whether over the counter or prescribed, have more than doubled from 1993 to 2012 going from 3 billion to 6.4 billion dollars.
CO2 extraction is the latest form of extracting oils from plant material and is a rather interesting process. Carbon dioxide is normally a gas at room temperature and under normal atmospheric pressure. When the gas is placed under extreme pressure, it takes on the characteristics of a liquid which gives it the ability to act as a solvent. The correct terminology for this extraction method is called, Supercritical CO2 extraction, since the carbon dioxide is in what is known as a supercritical state. Once the correct pressure is obtained, the supercritical CO2 dissolves the essential oils from the plant material. When the pressure is released, the CO2 turns back into a gas, evaporating into the atmosphere leaving behind only the oil.
In steam distillation, the plant material is placed above/in a steam bath so that the oils are dissolved by the steam. The vaporized oil and steam is then carried away from the plant material by a coil that passes through a condensing chamber. A cooling bath surrounding the coil brings the temperatures back down. This mixture of water and essential oil is called a 'hydrosol '. Once the temperatures of the hydrosol are cool enough, most of the oil separates from the water and rises to the top. The hydrosol is drained off and the pure essential oil is all that remains.
Cold pressing is a process that is mostly used for citrus oils. Distilled citrus essential oils are more unstable and deteriorate more quickly because of the heat involved, so mechanical extraction is preferred. In cold pressing, the rinds of the fresh fruits are shredded or ground and then pressed to literally squeeze out the oils. This method is not nearly as efficient as distillation, but the oil is of a far higher quality.
There are several methods used to extract essential oils from the plant material of aromatic plants. The most popular methods are steam distillation, cold pressing and CO2 extraction.
The International Organization for Standardization (ISO) currently defines essential oils as such: “An essential oil is a product made by distillation either with water or steam or by mechanical processing of citrus rings or by dry distillation of natural materials. Following the distillation, the essential oil is physically separated from the water phase.” According to this definition, a product extracted by the CO2 method must be considered an “Absolute” and not an essential oil.
The way essential oils work against germs is not limited to one or two mechanisms but instead, they cause a cascade of reactions involving the entire cellular structure of microbes. This is known as “essential oil versatility”. There are dozens of compounds that make up a single essential oil and each one may have a different effect on the cellular structure of germs.
Before the advent of modern medicine, professionals from ancient times used herbs to treat illness and ailments. Doctors of early times knew of the healing properties of the plants that surrounded us even before we learned to write. The Atharvaveda, an ancient text of Hinduism, dating back to about 1200 BC, documents early use of herbal medicines and forms the beginnings of Ayurveda.
In the 18th century, scientists began to extract and isolate the active constituents from aromatic herbs and determine exactly how they affected the different systems of our body. If fact, it is this research that has given us many of the worlds most successful drugs. Codeine, digoxin, ephedrine and lidocaine are just a few examples that originate from herbal sources.
Plants have adapted over the course of thousands of years for survival from predators and other organisms. Essential oils play a crucial role as a protection mechanism. Essential oils contain a wide variety of compounds that are designed to slow, stop the growth or kill bacteria, molds, viruses and yeasts. The components of essential oils are designed to target the outer walls and the fluid that fills the cells of these organisms. In some cases, essential oils completely change the structure of these life forms. These properties make them perfect for eco-friendly house cleaning.