Distillation is a process used for separating certain components or substances from a liquid mixture. There are many forms of distillation, some of the most common being steam, cold-press or expression, simple distillation, and fractional distillation. This unit will focus on two of these distillation methods, steam distillation and expression, because these are most often used when producing essential oils. Distillation can be used to produce pure essential oils, turn salt water into freshwater, refine oil for gasoline, and to accomplish many other things that affect our day-to-day living.
While distillation may sound pretty simple and straightforward, there are three vital factors within the distillation process that may affect the purity or potency of the substance being distilled. First, the heat source is an important consideration. If the temperature is too low, the distillation process will not be effective. If the temperature is too high, there is risk of damaging the substances being distilled and even collecting unwanted compounds. Second, it is vital to always be aware of the distillation time. In the case of essential oils, some plants may take only a few hours to distill, while others may need up to 36 hours. Lastly, if there is a pressurized system being used, the amount of pressure must be strictly controlled. Different materials require different levels of pressure. In-plant distillation, by increasing the pressure, the distillation time can be significantly reduced by up to 25 percent. A pressurized system can easily save time and money in the distillation process, but also requires careful monitoring to not ruin the substances being distilled.
Steam distillation works best for distilling compounds that are heat sensitive or volatile, which means that the substance can be easily evaporated. Such compounds are most often plant materials that produce essential oils. Steam distillation can be performed using a distillation still. When heat is applied to the water in the still, steam is produced. That steam moves through a chamber that houses the plant material. Each plant has small oil-filled sacs. When the steam collides with the plant material, the sacs break open and the oil comes out. The essential oils are then carried into a condensing tube by the steam where they gather in the collecting section of the still. Essential oils are not water-soluble, so the oil does not mix with the water. Instead, the water and essential oil naturally separate into two layers. The top layer consists of pure essential oil, while the water stays on the bottom, making it easy to collect the oil for bottling.
Expression is a form of distillation that does not involve heat. It is often referred to as “cold pressing” because the oil is obtained using mechanical pressure. Cold pressing is best used to extract essential oils from citrus fruits like lemons, bergamot, and oranges because it preserves the pungent odor of the fruit, whereas steam distillation would reduce the characteristic smell. Inside the expression, machinery are several rotating cylinders with large grates attached. As the fruit is added to the machine, those grates cut up the surface of the fruit. As the peels are scraped by the cylinders, small sacs containing essential oils break open and release the oil. As this process happens, water is sprayed over the fruit in order to collect the essential oil. To separate the pure oil from the water and the remains of the peels, the mixture is filtered from the machine into a device called a centrifuge. A centrifuge is a machine that rotates at a high speed in order to separate different liquids or solids from each other. This process allows the essential oil to be separated from the peel and water inside the machine.
Distillation is a common scientific process that has allowed people to collect and create pure products from the substances around us. doTERRA partners with the best distillation artisans from all over the world. Over the years, our partners have mastered the process of monitoring heat, temperature, and pressure of distillation machinery in order to obtain the perfect chemical composition of each essential oil. Artisans typically focus their efforts on distilling only a few different plants or plant products. This focus on distillation allows them to gain a level of expertise, knowledge, and experience that ensures we can produce the purest and potent essential oils possible.
Distillation has allowed doTERRA to access the incredible properties of hundreds of natural materials from all over the world. Careful regulation of these processes and the experience of our distillation experts are just two aspects of the doTERRA CPTG Certified Pure Tested Grade™ essential oils that you have come to know and love. The next time you use a bottle of doTERRA essential oil, just think about the expertise and scientific processes behind it!
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