Geranium Oil Extraction Process; Methods; Uses

The Geranium oil extraction process

Today, the topic is Geranium Oil Extraction procedure.

Introduction:

What is Geranium oil? Geranium is a perennial shrub with small pink flowers & pointy leaves that is native to South Africa. Out of the many varieties of the plant, Geranium (scientific name of GeraniumPelargonium graveolens) is the source of the essential oil. The oil is generally used in aromatherapy and contains a number of beneficial compounds. Geranium oil (Pelargonium graveolens) is a beautiful, floral essential oil often referred to as “the poor man’s rose oil” for its similar properties & uses. It’s sweet, the rose-like aroma is long-lasting & potent.

It’s traditionally used for healthy skin (repair or rejuvenation), as well as generally known for its emotional support. It commonly promotes peace and a decrease in stress, particularly in regards to releasing negativity, and is great for tension and overall well-being.

Geranium oil is a type of essential oil generally used in aromatherapy. Sourced from the flowers and leaves of the Pelargonium graveolens plant, the geranium essential oil is supposed to offer a variety of health benefits. Geranium oil contains a number of compounds thought to enhance health, including citronellol and geraniol.

Geranium oil is often compared to the rose essential oil since they share almost the same therapeutic traits. Geranium oil is often the alternative to the more expensive rose oil. There are several varieties of Geranium oil, based on where they are cultivated. The highest quality and most expensive form is produced in French island Reunion, called the Geranium bourbon essential oil.

Geranium Plant.
Geranium Plant.

Composition of Geranium oil:

Geranium oil contains nearly 67 compounds. The major components of Geranium oil are citronellol (26.7 percent) and geraniol (13.4 percent). Some other major constituents include:

  • Nerol (8.7 percent)
  • Citronellyl formate (7.1 percent)
  • Isomenthone (6.3 percent)
  • Linalool (5.2 percent)

Varieties of Geranium

  1. Algerian or Tunisian

This kind of Geranium is slender with flowers of a dark pink color. It is being developed in the Nilgiris and is unsuitable for wet conditions. Algerian variety yields 50-60% more oil with a more delicate odor than that of the Reunion type.

  1. Reunion or Bourbon

Grown in the Nilgiris and Anamalais, the plant is sturdier with light-pink flowers & more suitable for wet conditions. The oil content is higher through the summer months from April to June. The terminal portion with 6 to 12 leaves contains more oil than the middle & basal portions.

Geranium oil properties:

The Geranium oil is mostly colorless but can have a slight light green color to it. This oil has a watery viscosity.

Read: Cultivation Practices of Kodo Millets.

Harvesting:

Geranium is harvested about four to six months after transplanting when there is sparse flowering, leaves start turning light green color & exhibit a change from lemon-like odor to that of roses. Though the change in color and odor is the criterion for harvesting, it requires careful observations & experience to decide the stage of harvesting.

From field planting to first cutting it takes approximately 4 to 6 months. After the first cutting, three to five cuttings have taken a year. The frequency will depend on site fertility and rainfall or irrigation levels. Time of cutting is determined mostly by the state of growth. Detailed determination of the optimum time of cutting is dependent on a differ in the scent of crushed leaves from lemon-like to rose-like. Oil is concentrated in the leaves & young shoots. Old stems have very little or no oil. These must be cut off the plant, but removed from the young shoot material and left in the field. The plant is harvested when it has made an excellent level of new growth, but before a large number and weight of the old stems have been produced. Economic production is unlikely if less than three cuts have taken a year, although final assessment depends on the oil content of the plants at each cut.

At each cutting, if this is done manually, the entire canopy is removed with the exception of one complete branch which is left to continue to provide nutrients to the plant. When sufficient new leaf growth has been completed to support the plant growth, the remaining branch is cut. With mechanized forage harvesting, the complete canopy is cut, & care must be taken that the cutting height is not set too low, or regrowth will be slow, and the plants may die.

The crop is effectively a long term perennial and can remain in the field for ten or more years. Commercial life will depend on the health & vigor of the stand and the rotation requirements of the farm. 3 to 5 years may prove to be an economic & practical crop life.

Post-harvest:

The cut material must be distilled the same day as it is cut. Distillation is by wet steam. Oil yields must be in the range 60-70 kg/ha/yr.

Geranium oil contents:

The oil of Geranium is a clear liquid with light-yellow to light-brown color or green color. This oil has a strong, heavy rose-like odor with a minty top note. The chief constituents of the Geranium oil are geraniol and 1- citronellol, the quantities of which vary in proportion, depending upon the origin. Esters of these alcohols as acetates, formates, and tiglates are present. Other important constituents of Geranium oil are isomenthone, linalool,  turpineol, phenyl ethyl alcohol, 3-hexene-1-ol & rose oxides (traces).

Drying method:

The harvested material is spread out under shade in thin layers & is turned periodically to ensure proper drying. For higher recovery and good quality of oil, the moisture content of herbage must be between 8 to 10 %. Drying normally requires 3 to 6 days.  Properly dried leaves increase characteristic patchouli aroma, which is less noticeable in fresh leaves.

Geranium oil extraction:

The Geranium leaves and stalks are used for extraction, and the oil is obtained through steam distillation.  Steam distillation is the best process which gives better quality oil. Distillation takes 3 to 4 hours.

Steam distillation process:

Why do we use steam distillation? If water is used as one of the immiscible liquids the process is called steam distillation. It is used for purifying liquids which decompose at their normal boiling points. Steam distillation is used for separating organic compounds from plant elements.

Steam Distillation is the most popular method used to extract & isolate essential oils from plants for use in natural products. This happens when the steam vaporizes the plant material’s volatile compounds, which eventually go through a condensation & collection process.

What is the principle of steam distillation? The steam distillation process works on the principle that when a mixture of 2 or more undissolved liquids is heated. While ensuring that the surfaces of both liquids are in contact with the atmosphere, the vapor pressure exerted by the structure increases.

The oil is extracted from the whole plant using a distillation unit consisting of a distillation tank, a condenser, and a separator. Freshly harvested Geranium grass as such or after cutting into small pieces is loaded into the distillation tank. After closing the lid tightly, steam is passed into the distillation tank.

A large container called a Still, which is generally made of stainless steel, containing the plant material has steam added to it. Through an inlet, steam is injected through the plant material containing the desired oils, releasing the plant’s aromatic molecules & turning them into vapor. The vaporized plant compounds go to the condensation flask or the Condenser. Here, two separate pipes make it possible for hot water to exit & for cold water to enter the Condenser. This process makes the vapor cool back into liquid form.

The aromatic liquid by-product drops from the condenser & collects inside a receptacle underneath it, which is called a Separator. Because water & oil do not mix, the essential oil floats on top of the water. Now, it is siphoned off. (Some essential oils are heavier than water, such as clove essential oil, so they are found at the base of the separator.)

Steam and the oil vapor condense into liquid in condenser & are collected in the separator. The received oil is taken out, cleaned and stored either in aluminum containers or amber colored bottles. The recovery of oil from grass ranges from 0.3 to 0.6 percent. It takes about four hours for the complete recovery of the oil.

Read: Extraction Process of Almond Oil.

What are the advantages of steam distillation?

The advantages of steam distillation are as follows;

  • The amount of steam & the quality of the steam can be controlled.
  • Lower risk of thermal degradation as temperature normally not above 100°C.
  • Most generally used process for the extraction of essential oils on a large scale.

Cost of Geranium oil and Steam distillation unit:

Geranium oil (pure and natural) cost is Rs 15,000 to Rs 30,000/ Kilogram

Steam Distillation Unit cost approximately Rs 8 Lakh/ Piece

Storage and Packing of Geranium oil:

It is to be ensured that the Geranium oil does not contain any water before storage.  The Geranium oil is stored in glass bottles or drums made up of steel or aluminum depending upon the quantity of oil to be stored.  The containers are filled up to the brim, tightly capped & stored in a cool, dry and dark place.

That’s all folks about Geranium Oil Extraction Process.

Read: Techniques of Vertical Gardening.

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