Essential Oils Extraction Method Essential Oils Extraction Method

Posted on by Jackson Fung

Enfleurage:

One of the oldest method in essential oil extraction and it is rarely used nowadays. It is a very labor intensive and costly method and only used to extract oil from flowers such as jasmine.  The process involves spreading the flower petals on a glass called "chasis" and covering with vegetable oil or animal fat. The essence oil disperses into the grease and then the depleted petals are replaced with fresh petals. The process is repeated until the grease has fully abosorbed all the essence oil, then the grease is removed and is washed with alcohol to separate the essence oil from the grease. Essential oil absolute is produced after the alocohol evaporates.

Distillation:

The most common method of essential oils extraction is the steam distillation method. In this method, the plant materials to be used for extraction of essential oils are exposed to high pressure steam. As the steam is forced through the plant materials, it forces the pockets containing the aromatic compounds to open causing the compounds to evaporate into the steam. The temperatures of the steam should be high enough to force the release of the essential oils without causing damage to the plant material used. The steam containing the essential oils is then cooled to condense it to form a liquid mixture of water and the essential oil. Since water and oil are immiscible liquids and oil is less dense than water, the liquid mixture forms two layers with essential oil on top and water at the bottom. The two are then separated to obtain the essential oil and floral water which is a byproduct of the process.

Expression (Cold Pressed): This process involves the use of high mechanical pressure to force essential oils from the plant material.

Solvent Extraction:

Solvent Extraction method is often used on delicate plants. Carbon dioxide, Alcohol solvents such ethanol, or petroleum solvents such as hexane are used in this process. The solvent is absorbed when it is added to the plant material and allows the aromatic compounds to be released. The solvent extracted compounds are usually very concentrated and are known as absolutes. Below is a brief description of the three major solvents that can be used;

  • Petroleum Solvent, This has been the most common method of essential oils extraction in the past. However, residues of petroleum solvent may remain in the essential oils can cause skin irritation and allergic reactions.
  • Ethanol Solvent, This is a beverage alcohol unlike petroleum solvents is a safer solvent.
  • Carbon Dioxide, A more expensive method which during extraction, the temperature of carbon dioxide is increased to about 33 degrees Celsius under high pressure causing it to has liquid properties while maintaining in gaseous state. At this stage the CO2 acts as a solvent extracting essential oil out of the plant. The CO2 solvent is removed by lowering the pressure to convert to gas leaving behind pure essential oil without any residues.

Enfleurage:

One of the oldest method in essential oil extraction and it is rarely used nowadays. It is a very labor intensive and costly method and only used to extract oil from flowers such as jasmine.  The process involves spreading the flower petals on a glass called "chasis" and covering with vegetable oil or animal fat. The essence oil disperses into the grease and then the depleted petals are replaced with fresh petals. The process is repeated until the grease has fully abosorbed all the essence oil, then the grease is removed and is washed with alcohol to separate the essence oil from the grease. Essential oil absolute is produced after the alocohol evaporates.

Distillation:

The most common method of essential oils extraction is the steam distillation method. In this method, the plant materials to be used for extraction of essential oils are exposed to high pressure steam. As the steam is forced through the plant materials, it forces the pockets containing the aromatic compounds to open causing the compounds to evaporate into the steam. The temperatures of the steam should be high enough to force the release of the essential oils without causing damage to the plant material used. The steam containing the essential oils is then cooled to condense it to form a liquid mixture of water and the essential oil. Since water and oil are immiscible liquids and oil is less dense than water, the liquid mixture forms two layers with essential oil on top and water at the bottom. The two are then separated to obtain the essential oil and floral water which is a byproduct of the process.

Expression (Cold Pressed): This process involves the use of high mechanical pressure to force essential oils from the plant material.

Solvent Extraction:

Solvent Extraction method is often used on delicate plants. Carbon dioxide, Alcohol solvents such ethanol, or petroleum solvents such as hexane are used in this process. The solvent is absorbed when it is added to the plant material and allows the aromatic compounds to be released. The solvent extracted compounds are usually very concentrated and are known as absolutes. Below is a brief description of the three major solvents that can be used;

  • Petroleum Solvent, This has been the most common method of essential oils extraction in the past. However, residues of petroleum solvent may remain in the essential oils can cause skin irritation and allergic reactions.
  • Ethanol Solvent, This is a beverage alcohol unlike petroleum solvents is a safer solvent.
  • Carbon Dioxide, A more expensive method which during extraction, the temperature of carbon dioxide is increased to about 33 degrees Celsius under high pressure causing it to has liquid properties while maintaining in gaseous state. At this stage the CO2 acts as a solvent extracting essential oil out of the plant. The CO2 solvent is removed by lowering the pressure to convert to gas leaving behind pure essential oil without any residues.