The most recent method is that of the distinguished carbon dioxide extraction. It employs a much lower temperature than that of steam distillation. This process was to introduce oils that remain close to the way they reside in nature. This is primarily due to the inert nature of the solvent and lower pressures. There is some disagreement to this theory in that due to the acidic nature of CO2 one could argue it is disruptive to the chemistry of the resultant oil. Whereas terpenes are often manufactured through the methodology of distillation, a lower terpene content is produced through a CO2 extraction, a higher ester range is manufactured, and the addition of molecules far to large to pass their way over through distillation can be found. These findings confirm that the oil does have more of the botanics inherent personality.
This extraction employs a family of benign non-CFC gaseous solvents, R134a, or refrigerant Hydroflurocarbon 134a, now called ‘florasol’. Beginning to replace CFC’s, chlorinated flurocarbons, in the early 1980’s it won the curiosity of the British microbiologist, Dr. Peter Wilde.
Dr. Wilde brought this process into the spotlight of the essential oil manufacturing community, inventing the innovative extraction method of Phytonic Extraction. Being now in development over the past 10 years, the extracts were once called ‘phytols’, then ‘phytosols’ and now referred to as ‘florasols’
A rather new methodology developed and used by French companies produces a ‘Butaflor’. Butane is used as the solvent. One of the advantages in it’s employment is that the boiling point is low and therefore can be removed easily without much heat or a high vacuuming. Unfortunately, the nature of Butane is caustic and makes it highly flammable, difficult to work with and contributes to the depletion of the ozone. Completely and utterly environmentally undesirable.
Rarely applied to the Fragrant Essence trade today, except in some unusual cases such as with Tuberose, this remains the oldest truly ‘traditional’ methods of extraction. Once used to create treasured pomades and floral ‘creams’, it is by far the most laborious, expensive and time consuming extraction method.
Sheets of glass are prepared by coating them with bland warmed oils, fats, in particular cold fats such as lard, or waxes. Once prepared the sheets of glass are gingerly stacked one on top of another. Over a period of weeks the flowers will deteriorate, and continually be replaced by fresh blooms until a saturation level is reached. The waxy infusion, now nearly 1% buying pure essential oil, referred to as a ‘pomade’ is then collected . The pomade is then subjected to an alcohol washing to be shaken for several hours in order to remove the essence from the fat at which time the alcohol will be evaporated off leaving a pure enfleurage, often referred to as the ‘absolute’. The yield of a enfleurage is quite voluminous in comparison to a solvent extraction.
Whereas an extract employs alcohol this method requires a ‘fatty’ base, such as a vegetable or nut oil. It involves soaking the botanical materials in the heated compound. The petals and leaves will soften and the cellular structure will break down and release their aromatic and therapeutic contents.
This method was once commonly referred to as ‘Scarification’ and employs pressure to the peel of Citrus fruits such as Grapefruit, Lemon, Lime, Orange and Mandarin, and results in puncturing and squeezing out the zest of the peel. Then the peels are misted with a finite spray of water. By these techniques a ‘cold’ method of extraction is obtained. At one time the oil rich rind of these fruits were squeezed by hand and collected into a mighty sponge. Some of the Mediterranean oils still use this age old method rather that relying on reckless machines and the technology of centrifugal force to do the work. Some fruits, such as bergamot, have their peels separated and ‘cold pressed’.
Note: due to the enormous demand of Citrus extracts, the quality available to the public today can be quite objectionable. Many are an aftermath of major juice manufacturers adding Citrus extracts as a side commodity to their business — after they have separated fruit, pith and juice.