How Is Pure Eucalyptus Oil Made?

Eucalyptus oil is a natural essential oil that is steam distilled from the leaves of Eucalyptus trees. Pure eucalyptus oil contains the natural aromatic compounds found within eucalyptus leaves and has a variety of uses. It is most commonly known for its purifying and cleansing properties.

Pure eucalyptus oil has many benefits and uses:

• It contains antioxidants that support the immune system.
• It has antimicrobial properties that act as a cleaning agent.
• It supports respiratory health when inhaled or applied topically.
• It has a refreshing, energizing scent that is soothing and clarifying.
• It can be diffused, applied topically, or used as an ingredient in personal care products.

Eucalyptus Trees

There are more than 700 species of eucalyptus trees native to Australia and northward through the Philippines, Indonesia and New Guinea. Eucalyptus trees are fast-growing trees typically reaching 33–230 feet in height and can thrive in a variety of soil types, including poor soils. The leaves of eucalyptus trees hang vertically and are often covered with a white, waxy bloom that helps retain moisture in the leaves during dry seasons and hot summers.

The primary species used for extracting eucalyptus oil are Eucalyptus globulus (also known as blue gum eucalyptus) and Eucalyptus polybractea (also known as blue-leaved mallee). E. globulus grows up to 230 feet tall and thrives along the southern coast of Australia. E. polybractea is a smaller mallee eucalyptus that only grows to about 20 feet tall and is found throughout Australia. Both species produce high quality eucalyptus oil rich in eucalyptol, the primary desired constituent.

Leaf Harvesting

Leaf harvesting is carefully timed to pick the eucalyptus leaves when their oil concentration is at its peak. The ideal time is when the leaves are fully mature but before flowering. This generally occurs 4-5 years after the tree is planted.

Leaves are hand-picked or harvested mechanically. Hand picking is more precise, but slower. Mechanical harvesting uses modified forage harvesters that use blades to cut the leaves and branches from the trees. The machinery grabs the cut foliage and sends it into collection vehicles.

Hand picking is done by skilled workers who climb the trees and selectively pick mature leaves. They take care to leave younger leaves and branches intact for future harvests. The freshly picked leaves are gently handled to minimize bruising.

Mechanical harvesting is faster but less targeted. It indiscriminately cuts any foliage within reach. The harvested material requires extensive sorting to remove twigs, bark and immature leaves before distillation. Bruising of the leaves also reduces oil quality. However, mechanical harvesting may be more economical for very large operations.

Regardless of method, the freshly harvested leaves need to be quickly transported to prevent spoilage. Careful planning ensures harvested leaves undergo distillation within 24 hours (Ebay, 2023).

Leaf Transportation

After the eucalyptus leaves are harvested, they need to be transported to the distillation facility for processing. This is often done using large trucks that can hold high volumes of loose leaves. The trucks are specially designed with open tops or side panels so the leaves can be easily loaded and unloaded (Hartsough B., Harvesting eucalyptus for fuel chips).

Care must be taken during transportation to prevent compressing or bruising the leaves, which can negatively impact oil yield. The leaves are loosely packed into the trucks, often no more than 2-3 feet deep. Shorter transportation distances are preferred to minimize handling. Leaf moisture content is also monitored and controlled prior to transport using forced air drying if needed. This helps prevent composting and deterioration during transit (Cunningham, A. B. Eucalyptus Oils).

Trucks may make multiple trips per day between the harvest site and distillation facility to ensure fresh leaves are continually fed into the distillation process. The timing of the transports is coordinated based on distillation batch schedules. Efficient route planning minimizes transportation costs and elapsed time from harvest to processing.

Leaf Processing

Before the eucalyptus leaves can be distilled into oil, they go through several processing steps to prepare them for extraction. The first step is drying the freshly harvested leaves, which helps release the oil from inside the leaf cells.https://www.ethosnatura.com/what-is-steam-distillation-of-essential-oils/ The leaves are left to air dry in the sun for several days, which reduces the moisture content and makes the leaves brittle. Once dried, the leaves are then crushed or ground into a coarse powder or flakes. This increases the surface area of the leaves and further releases the essential oil contained within.

According to one review, the particle size of the crushed leaves can impact oil yield during distillation. Finer flakes or powders provide more surface area and can increase extraction efficiency compared to coarser grinds.https://iopscience.iop.org/article/10.1088/1755-1315/733/1/012103/pdf However, too fine of a powder can clog the distillation equipment. Most processors aim for a coarse flake or powder grind that maximizes surface area without impeding steam flow.

Distillation Process

The distillation process is where the eucalyptus oil is extracted from the leaves. It involves using steam distillation equipment and carefully controlling temperature and pressure.

The leaves are placed into a large distillation tank or still. Steam is injected into the bottom of the tank at high pressure. The steam causes the oil stored in glands in the leaves to evaporate. As the steam rises through the leaves it collects the vaporized eucalyptus oil.1

The steam and oil vapor mixture then travels through a condenser. The condenser cools the vapors causing them to condense into a liquid. The liquid separates into water and eucalyptus oil due to differences in density. The oil floats to the top and is siphoned off while the water is drained from the bottom.

Multiple distillation runs may be required to fully extract the oil from the leaves. The distillation process requires careful control of temperature, pressure and steeping time to obtain the highest quality oil.2

Oil Separation

After distillation, the eucalyptus essential oil is mixed with the distilled water or hydrosol. To separate the oil from the water, the mixture is transferred into a separation vessel and allowed to settle. The essential oil, being less dense than water, floats to the top while the hydrosol stays at the bottom.

Some methods employ a Florentine flask which allows the essential oil to flow out through the side arm while the hydrosol remains in the flask [1]. Other common separation techniques include using a separating funnel or gravity separation where the oil and hydrosol layers are simply decanted from one another.

Once separated, the essential oil goes through further processing while the hydrosol can be used for various purposes. This separation step allows the pure eucalyptus essential oil to be effectively extracted from the distillate.

Oil Processing

After the eucalyptus oil is separated from the water during distillation, there are additional steps to produce pure eucalyptus oil. The crude eucalyptus oil collected from the distillation process contains impurities and water that need to be removed.

The oil first goes through a filtering process to remove any residual plant matter. This is done by passing the oil through a series of fine filters and screens to remove particles and solids.

Next, the filtered oil goes through a settling or decanting process. The oil is left to sit undisturbed in large settling tanks, allowing any remaining water and heavier particles to sink to the bottom. The pure eucalyptus oil is then decanted or siphoned off the top.

According to a patent filed by Guangdong Fumei Daily Chemicals Co., Ltd, the oil may also undergo a chemical drying process using calcium oxide to absorb any residual moisture [1].

Finally, the purified eucalyptus oil is tested to ensure it meets quality standards for color, scent, purity, and chemical composition before being packaged for distribution and sale.

Quality Testing

Once the pure eucalyptus oil has been extracted and processed, it undergoes rigorous quality testing to ensure its purity and therapeutic-grade quality before being packaged and distributed. There are several methods used to test the quality and purity of the finished eucalyptus oil:

Gas chromatography-mass spectrometry (GC/MS) is the gold standard for testing essential oil purity and quality. This lab testing method separates and analyzes the individual chemical components in an essential oil to detect any adulterations or contaminants. Only oils verified with GC/MS testing can be considered 100% pure therapeutic grade.

Organoleptic testing involves using the human senses of sight, smell, and taste to evaluate an essential oil. High quality eucalyptus oil should have a fresh, camphoraceous aroma and a water-white color when viewed in the proper light. Taste testing should produce a cooling sensation on the tongue.

The drop test is a simple and inexpensive way to get an initial assessment of oil purity at home. Place a drop of oil on paper – a pure, high quality essential oil will gradually evaporate without leaving any oily residue.

Checking the specific gravity or density of an oil can verify its purity. Quality eucalyptus oil should have a specific gravity of 0.906 to 0.927 at 15°C.

Other standard quality tests check purity parameters like optical rotation, refractive index, flash point, and solubility.

Reputable essential oil companies will provide third-party testing reports to back up their claims of purity. Only purchase oils that have been properly tested.

Packaging & Distribution

Once the pure eucalyptus oil has been tested thoroughly for quality, it is ready for packaging and distribution to buyers. The oil is carefully bottled into amber or blue glass bottles to protect it from light exposure. Common bottle sizes range from 4oz to 16oz, though larger bulk sizes are available as well. Each bottle is labeled with the product details, batch number, and expiration date.

For bulk orders, the oil may be packaged into larger stainless steel drums able to hold 5-55 gallons. These drums are transported via trucks to distribution warehouses. From there, the oil is shipped domestically or internationally according to buyer demand. Major importing countries include the United States, France, and Germany.

Proper packaging and handling procedures are critical to preserve the integrity of the eucalyptus oil. Exposure to heat, light, or oxygen can cause the oil to deteriorate. The supply chain is designed to minimize transit time and environmental factors. With prompt delivery in amber glass or steel containers, the pure therapeutic-grade oil arrives safely to retailers, manufacturers, and aromatherapists.