How Essential Oils Are Made, A Guide
Essential oils are released from the biological matter as vapor. The vapor then travels through a condenser. The condenser has two separate pipes, including one for cold water to enter the condenser and cool the vapor into liquid form. The hot liquid, containing the essential oils, travels from the condenser in the exit pipe. The liquid containing the essential oil goes from the condenser into a separator that siphons off the oil from the water.
Solvent extraction is another popular extraction method for essential oils that will be used in perfumes, soaps, or aromatherapy. It is not suited for oils that will be ingested. Mostly, it is used on plants that are either too fragile for steam distillation or so resinous that steam distillation doesn't extract a usable amount of essential oils. One of the benefits of solvent extraction is that it maintains more of the plants' smell than other methods, which also makes it well suited to be used for essential oils destined for aromatherapy and perfume. Solvent extraction begins by applying a food-grade solvent such as ethanol or hexane to the plant, which causes the plant to excrete a compound known as a concrete that contains the essential oils of the plant. The concrete is then mixed with alcohol, which causes the oil to separate from the rest of the compound.
CO2 extraction also results in oils suitable for use in perfumes and aromatherapy. The quality of the oil extracted is dependent upon factors such as the amount of time, the amount of pressure, and the temperature used during the process. Unlike what happens during steam distillation, CO2 doesn't damage the molecules found in the oils. Oil extracted using the CO2 process tends to be thicker than oils extracted using other methods and also has a much stronger scent. CO2 is the chosen gas for the process because it doesn't have its own odor. The process begins when carbon dioxide, which has been pressurized into a supercritical state (meaning that it behaves like a liquid while remaining a gas), enters the chamber with the organic matter. The CO2 acts as a solvent that pulls out the essential oils and other substances from the plants and herbs. Next, the CO2 leaves the chamber, and the pressure is released, allowing it to return to its natural state. At this point, the essential oil is left behind as the CO2 once more becomes gas.
The more common name for oils extracted using the maceration process is infused oils. Basically, oils known as carrier oils are used as solvents to extract essential oils from plants or herbs. Maceration allows for more of the essence of the plant to be present in the final product. It does this by being able to capture and hold larger molecules than those captured through the process of distillation.
The first step of the maceration process is to dry the plant material as thoroughly as possible. Moisture can cause the oil to become rancid very quickly. Next, the plant or herb is either ground or cut into a coarse powder before being placed in a closed container. A carrier oil is added, and the container is stored for a week or more. During this time, it is sometimes shaken. When this step is finished, the liquid is strained and clarified.
Citrus peels used for making essential oil are often extracted using the cold-press extraction method. Here, the fruit is left whole until it is probed mechanically, a process that opens the essential oil sacs located in the fruit's rind. The essential oils fall down into a collection flask underneath the device. Then, the entire fruit is crushed, and bits of pulp and other solids are removed by using a centrifuge. The final step of the process is when the oil is separated from the juice.