The Difference Between Steam Extraction and CO2 Extraction
Humans have been extracting essential oils from plants for centuries, but only with modern technology are we finally beginning to hone the distillation process into one which is fast, effective, and which produces the highest-quality essential oils.
Until recently, the most popular method of extraction was steam extraction, which involved using carefully temperature-controlled steam to capture the essential oils. Now, a new and more modern technique, CO2 extraction, has begun to replace it as a newer and more modern extraction method.
What are the differences between steam extraction and CO2 extraction? Keep reading to find out:
What is Steam Extraction?
Steam extraction, or steam distillation, is a separation process used for natural aromatic compounds which are temperature sensitive. For many decades, this method was popular for extracting essential oils from plants but is currently being replaced by the more efficient method of CO2 extraction.
How Does Steam Extraction Work?
Steam extraction functions by passing steam through plant material which has been stored in a large holding tank or chamber, known as a “distillation column”. This allows for the essential oils to be extracted at a low temperature which will not damage the plant matter.
As the steam is released and passes through the organic plant material, tiny pockets which hold the essential oils will open and release the oil molecules into the air without causing any damage to the distillate.
The final result will consist of a mixture of water vapor and essential oils which will return to a liquid form when cooled.
What is CO2 Extraction?
CO2 extraction is a modern extraction process for pulling essential oils from plant matter. With CO2 extractions occurring at lower temperatures in what is known as "cold separation", CO2 extraction is quickly replacing steam distillation as the true botanical character of the plant material is better preserved.
CO2 extraction, also known as “supercritical carbon dioxide extraction” involves using highly pressurized carbon dioxide to extract the essential oils from plant matter in a method which is faster, more energy-efficient, and yields better results than other extraction methods.
How Does CO2 Extraction Work?
CO2 extraction is a similar process to steam extraction, but with a few key differences. Keep reading to learn the steps associated with this extraction method:
- Filling the holding tank. Plant matter is placed in a holding tank which is pumped with highly pressurized CO2.
- Going “supercritical”. When CO2 is sufficiently pressurized it will become “supercritical” and will remain in a gaseous state while still exhibiting some of the characteristics of CO2 in its liquid state.
- Acting as a solvent. Supercritical CO2 acts as a solvent which draws out the essential oils without causing damage to the plant matter.
Benefits of CO2 Extraction vs. Steam Extraction
Some of the benefits associated with CO2 which make it a better extraction option include:
- A better result. CO2 extraction delivers a result which retains more of the smells and colors associated with the plant than can be extracted using a steam-based method.
- No solvents. CO2 extraction reduces pollution by negating the use of harmful solvents such as hexane, which are typically used during extraction processes.
- Longer lasting results. Essential oils which are extracted using this method retain their scent and have a longer shelf life.