Tuesday, August 9, 2016

A Rose is a Rose is a Rose

That is, a Rose Essential Oil, a Rose CO2 Extraction, a Rose Absolute!

Maybe we’re biased, but our Nature’s Gift Facebook friends and followers ask the best questions week after week during our one hour live Mondays with Marge at 8:00 p.m. CDT.  Marge fielded a variety of questions this week including thoughts on antispasmodic essential oils, lovely Rose oils, Clary Sage varieties and more!  

Cindi: Hi Marge, Can you explain the difference between an Essential Oil, an Absolute and a CO2?
Marge: Thanks, Cindi. The main difference is the method of production. Different methods of production (extraction) will yield different products, and some plants are more appropriately extracted by one method or another. (Main types are: Steam or Hydro Distillation of Essential Oils, Co2 Extraction of Essential Oils, and Solvent Extraction of Absolutes.)  Another method for another day is an ancient/early method called “Enfleurage.” 
Savory oil and hydrosol in Separator
First, essential oils...with the exception of cold pressed citrus oils…which break every rule! Essential oils are volatile products of distillation, either steam distillation (where the still is packed with the biomass, and steam is piped into the bottom, breaking the cells that hold the essential oils and carrying the essential oil with it, as it exits the still) or by hydro-distillation, where the biomass is put IN the water, directly. The water is then heated, and the steam from the heated water carries the essential oil with it as it exits the still. In both cases above, the aromatic steam goes through a cooling coil to rapidly cool it, back to water, and drains into a separator. In almost every case, the aromatic water separates with the essential oil floating on top, and the water based distillate, the hydrosol, sitting on the bottom.

CO2 extracts are a relatively new technology; I think commercially available perhaps only during the last 30 or so years. CO2, Carbon Dioxide, the gas that we exhale with every breath, is chilled under sufficient pressure to cause it to turn liquid. This liquid CO2 is used as a solvent, extracting both the volatiles (the essential oil) and plant components, plant waxes, and other components that do not come across during the process of distillation because their molecules are too heavy to exit the still with the steam. CO2 extraction can give us extracts of plants that may not otherwise be distilled, which don't produce an essential oil: Calendula and Sea Buckthorn are examples. The results are closer to absolutes than to essential oils because the botanicals do not go through the heating process of distillation—perhaps this is why the aroma is closer to the plant. The CO2, acting as solvent, just evaporates off into the surrounding air, with nothing left behind.
Now on to Absolutes! Absolutes are produced in two steps, by the use of solvents. In the initial step, the fresh blossoms are washed with a solvent, most commonly hexane. This removes both the aromatics and the floral waxes, and gives a product called a CONCRETE. This concrete is normally solid, ranging from fairly soft to almost rock hard. The concrete may be stored as such and is sometimes available on the commercial market. The second step is washing the concrete with Ethanol (Alcohol) to separate the aromatic oils (the Absolute) from the Floral Wax. After this separation is accomplished, the ethanol SHOULD be all evaporated off, leaving a pure absolute, although I have seen so-called absolutes available commercially that both based on the price, the color, and, most important, the aroma, obviously had a fair amount of Ethanol left in them. In a well-produced absolute, the level of residual solvent should be on the level of a very few parts per million, thus not a concern.  Absolutes are most often used by perfumers, rather than in Aromatherapy.
There are advantages to each method. For therapeutic use, purists still request the distilled oils The CO2s offer more components from the botanical that can't exist in the distilled oil (see our discussion about Incensol Acetate in Frankincense CO2, for example.) The process of Absolute production will allow the essence of blossoms that cannot be distilled such as Lotus, Osmanthus, etc. Both CO2 and Absolute will give a larger volume of product from the same amount of botanical.
From an aromatic standpoint, I have always considered the traditional distilled oil to be the least aromatic, the CO2 extract to be much closer to the fresh plant, and the absolute the aromatic pinnacle of our ability to match a blossom. 
Rose is one of the finest examples, for instance.  Today we had a wonderful chance to sample all three extractions from one blossom. We received samples from our Bulgarian supplier, and not only the Rosa Alba CO2 came in, but a small sample of Rosa Damascena CO2 extract, as well as a wee sample of this year’s Rose Otto— the distilled Rosa damascena. We also have last year’s Rosa Damascena absolute, from Bulgaria, so were able to experiment and experience all three. As I said in an email to the producer, "I'm floating on a rose-scented cloud and NOT going to get any work done today!" (I left those scent strips at the office, if I had brought that fan of aromas home I would NOT be answering questions this evening!) This is the array of scent strips, with the wee folk art holder that contains a ml of 2016 organic Rose Otto.
Scent strips, L to R, Rose Abs,Bulgarian, Rose Otto, Rosa Damascena CO2 and Rosa Alba CO2

Have a nagging aromatherapy question?  Join us Monday night for Mondays with Marge, 8:00 p.m. CDT on our Facebook page. 
Questions must be posted under the Mondays with Marge graphic.  When it (the graphic) appears late Sunday or early Monday, questions may be posted for the Monday night session.

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