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What is CO2 Extraction?
(For a
descriptive list of the CO2 Extracted Oils
available at Nature's Gift,
please click here.)
My respected colleague, Susan Renkel at Changes Within shared the following some time ago on one of the Aromatherapy Lists.
She graciously gave me permission toquote her rather than reinvent the wheel.
CARBON DIOXIDE EXTRACTS
Hypercritical carbon dioxide extraction is a relatively new process
used to extract the essence of the plant. When a certain amount of
pressure is applied to CO2 (carbon dioxide) this gas turns into liquid.
This liquid CO2 can be used as a very inert, safe, "liquid solvent." CO2
is the gas we all breathe out of our lungs. It is also the gas that plants
themselves thrive on. Essential oils extracted in this way have the added
benefit of avoiding the thermal degradation associated with distillation at
atmospheric pressure.
Two types of materials are obtained by this CO2 method:
Essential oils or CO2 Selects:
are obtained at relatively low CO2 pressure and contain only volatile, CO2 soluble components. These tend to resemble
the classic steam distillate but with the advantage of no temperature
degradation and the potential for additional volatile substances that may
not be distilled out of the plant under normal steam distillation.
Extracts called "totals"
are obtained at higher CO2 pressures and
contain all CO2 soluble components, including waxes, resins, colorants,
resembling a classical hexane extract, with the advantage of no solvent
residue. These totals are very very much like the herb itself.
The consistency of the essential oils
extracted with the CO2 method
will vary from batch to batch just as the plants themselves vary and just as
steam distilled oils vary. Naturally, there is also the extraction process
itself and the actual processor to consider.
CO2 totals
are usually thick and pasty due to the beneficial fats,
resins and waxes they contain that come from the plant material itself.
These totals are soluble in essential oils and vegetal oils. Some, such as
rosemary verbenone must be warmed with the vegetal oil or by itself and then
quickly added to WARM oil in order to be soluble. It is the same thing for
some of the others like sea buckthorn berry or vanilla CO2. Even small
percentages of (.05% to 1 % ) of these CO2 extracts can be excellent
additions to body oils, creams, ointments, lotions, balms, soaps or
essential oil blends. Because of the sometimes thick, pasty nature of
these CO2 oils, they should not be used in a nebulizer type diffuser. They
could clog your diffuser.
USES:
These potent extracts are wonderful for cosmetics and pharmaceuticals.
The Calendulas extract, for example, in a dosage of 2 grams extract to 1000
grams ointment is effective for it's anti-inflammatory and anti-microbial
activity. The chamomile CO2 extract or "total" contains 6% bisabolol
and 2.8% matricin. The matricin is not degraded to chamazulene,
Chamazulene has only one tenth of the anti-inflammatory activity as matricin.
CO2 extracts have a minimum shelf life of one year. They should be
kept under the same conditions as steam distilled essential oils ... that is
in a cool, dark place, in full glass containers.
Hypercritical carbon dioxide extraction appears to be an
aromatherapist's (and herbalist's) dream come true (in some respects).
Unlike the products produced by regular solvents (absolutes and concretes)
the solvent (CO2) can be easily and totally removed, just by releasing the
pressure in the extraction chamber. This process, because it happens in a
closed chamber, can then collect the most volatile and most fragile
fractions of the fragrance and plant. The end result; an extract as close
to the natural essence of the plant that anyone has achieved, except
perhaps, the new "florasols" that Peter Wilde is/was (?) producing.
This information is copyrighted by Susan Renkel RN / 1998 and can not
be reproduced by any means without express written permission by the author.
For a list of the CO2 Extracted Oils
that we offer, please click here.