| erapy Goes 'High Tech' | | | | processed using ethyl alcohol (the same alcohol found |
| New methods of essential oil extraction are entering | | | | in beer, wine, etc.) in which the wax is only slightly |
| the mainstream of aromatherapy, offering new | | | | soluble. The volatile plant oil separates into the alcohol |
| choices in oils never before available. With the new | | | | and this mixture is removed. The alcohol is then |
| labels of 'CO2' and 'SCO2', along with the traditional | | | | evaporated and the result is an almost pure plant |
| 'steam' and 'hydro' distillations, 'absolutes', and 'cold | | | | extract — depending on the care taken in the |
| pressing', a little education for the aromatherapy | | | | evaporation process, sometimes 2% or less of the |
| enthusiast can go a long way in essential oil selection. | | | | ethyl alcohol may remain. The use of solvents in the |
| Is one process better than another? Does one | | | | extraction process notwithstanding, absolutes can |
| produce a nicer smelling oil, or one with greater | | | | have incredibly deep and complex aromas. |
| aromatherapeutic value? It turns out that essential oil | | | | CO2's and SCO2's |
| production, like winemaking, is an art form as well as a | | | | And now for the most modern technologies, Carbon |
| science. The value of the newer processing methods | | | | Dioxide and Supercritical Carbon Dioxide extraction. |
| depends greatly on the experience of the distiller, as | | | | Both methods involve the use of carbon dioxide as the |
| well as the intended application of the final product. | | | | 'solvent' which carries the essential oil away from the |
| Each method is important, and has it's place in the | | | | raw plant material. The lower pressure CO2 extraction |
| making of aromatherapy-grade essential oils. | | | | involves chilling carbon dioxide to between 35 and 55 |
| Steam and Hydro Distillation | | | | degrees F, and pumping it through the plant material at |
| Steam distillation, the most common method of | | | | about 1000 psi. The carbon dioxide in this condition is |
| essential oil production, involves the flow of steam into | | | | condensed to a liquid. Supercritical CO2 extraction |
| a chamber holding the raw plant material. The steam | | | | (SCO2) involves carbon dioxide heated to 87 degrees |
| causes small sacs containing essential oil to burst. The | | | | F and pumped through the plant material at around |
| oil is then carried by the steam out of the chamber | | | | 8,000 psi — under these conditions, the carbon |
| and into a chilled condenser, where the steam once | | | | dioxide is likened to a 'dense fog' or vapor. With |
| again becomes water. (Hydro-distillation is a similar | | | | release of the pressure in either process, the carbon |
| process where the plant material is boiled, with the | | | | dioxide escapes in its gaseous form, leaving the |
| resultant steam being captured and condensed). The | | | | essential oil behind. |
| oil and water are then separated; the water, referred | | | | These carbon dioxide methods have a couple of |
| to as a 'hydrosol', can be retained as it will have some | | | | advantages: Like steam distillation, there are no solvent |
| of the plant essence. Rose hydrosol, for example, is | | | | residues left behind, and the resultant product is quite |
| commonly used for it's mild antiseptic and soothing | | | | pure. Like solvent extraction, there is no heat applied to |
| properties, as well as it's pleasing floral aroma. | | | | the plant material or essential oil to alter it in any way. |
| A number of factors determine the final quality of a | | | | The oil produced is very accurate with respect to the |
| steam distilled essential oil. Aside from the plant | | | | original state of the plant. The CO2 methods also are |
| material itself, most important are time, temperature | | | | the most efficient, producing the most oil per amount |
| and pressure, and the quality of the distillation | | | | of plant (one of the reasons for the high cost of |
| equipment. Essential oils are very complex products; | | | | essential oils is the low yield of oil from most plants |
| each is made up of many, sometimes hundreds, of | | | | — one ton of Rose petals produces less than 1 |
| distinct molecules which come together to form the | | | | pound of oil, for example). The efficiency of CO2 |
| oil's aroma and therapeutic properties. Some of these | | | | extraction is particularly important when rare or |
| molecules are fairly delicate structures which can be | | | | endangered plant species are involved, such as Indian |
| altered or destroyed by adverse environmental | | | | Sandalwood oil — less of the precious plant is |
| conditions. So, much like a fine meal is more flavorful | | | | needed to produce an equivalent amount of oil. |
| when made with patience, most oils benefit from a | | | | Cold Pressing |
| long, slow 'cooking' process. | | | | Finally, there is the 'cold pressing' of citrus oils from the |
| The temperature of the extraction chamber cannot be | | | | peels of fruit, as is done with Bergamot oil, Orange oil , |
| too high, lest some components of the oil be altered or | | | | Lemon oil , and the like. This method involves the simple |
| destroyed. The same is true of the chamber's | | | | pressing of the rind at about 120 degrees F to extract |
| pressure. Lavender essential oil, for example, should | | | | the oil. Little, if any, alteration from the oil's original state |
| not be processed at over 245 degrees F and three | | | | occurs — these citrus oils retain their bright, |
| pounds per square inch of pressure (3 psi). Higher | | | | fresh, uplifting aromas like that of smelling a wonderfully |
| temperatures and/or pressures result in a 'harsh' | | | | ripe fruit. |
| aroma — more chemical than floral — | | | | Which Method is Best? |
| and lessen the oil's therapeutic effects. Also, the | | | | CO2's, with some obvious advantages, are not always |
| extraction period must be allowed to continue for a | | | | the best choice for a particular need. They still are the |
| certain period of time in order to flush ALL the oil's | | | | most expensive, despite their higher yields. The |
| components from the plant, as some are released | | | | resultant product differs slightly compared to one |
| more quickly than others. | | | | produced another way — the oils produced by |
| Despite the drawbacks of aggressive processing, high | | | | steam distillation of some plants may sometimes be |
| temperatures and pressures are often used to | | | | found to have a more agreeable aroma. Patchouli oil, |
| produces large quantities of oil in a short period of time. | | | | for example, seems to benefit from the steam |
| These oils are usually destined for use in cosmetic and | | | | distillation process by becoming a little warmer and |
| processed food manufacturing, but are sometimes | | | | richer. Many other essential oils are quite effectively |
| sold to final consumers as essential oils for use in | | | | produced via steam distillation, with little alteration from |
| aromatherapy. These oils will be less expensive, but | | | | the original plant state. Oils from other plant species do |
| are of limited therapeutic value, and the difference is | | | | seem more 'complete' with CO2 processing, with |
| apparent when the aromas are compared | | | | Frankincense oil and most of the 'spice' oils being good |
| side-by-side. | | | | examples where a little something special is present in |
| Absolutes | | | | the aroma. This likely translates to greater therapeautic |
| Some plants, and particularly flowers, do not lend | | | | properties. |
| themselves to steam distilling. They are too delicate, or | | | | Producing essential oils of aromatherapeutic grade is |
| their fragrance and therapeutic essences cannot be | | | | skill requiring years of experience. It takes the work of |
| completely released by water alone. These oils will be | | | | a dedicated artesian at every step, from growing and |
| produced as 'absolutes' — and while not | | | | harvesting to fine-tuning the distillation process, to |
| technically considered essential oils they can still be of | | | | produce a truly fine oil. The making of a fine essential |
| therapeutic value. Jasmine oil and Rose oil in particular | | | | oil relies far more on knowledge and experience than it |
| are delicate flowers who's oils are often found in | | | | does on the particular extraction method. There are, |
| 'absolute' form. | | | | however, legitimate reasons to select one distillation |
| The processing of an absolute first involves the | | | | method over another — some plants simply |
| hydrocarbon solvent extraction of a 'concrete' from | | | | require a particular process to produce a fine oil, and |
| the plant material, a semi-solid mixture of typically 50% | | | | the oil needed for a particular application may only be |
| wax and 50% volatile oil. The concrete is again | | | | made by one process. |