The essential oil of vetiver is extracted through the distillation of the plant's roots, as the above-ground biomass contains no oil. Vetiver oil, with its heavy, woody, and earthy character, is one of the perfumer’s most basic and traditional, and commonly used materials/substances. It serves as a key ingredient in 36% of premium perfumes (mostly sold in the and 20% of men's fragrances, including famous names like Chanel No. 5, Miss Dior, Cravache, and Shalimar. This oil is highly prized as a 'base note' in fragrance and flavor production.
Types of Vetiver Distillation Methods:
There are two primary methods for extracting essential oil from vetiver roots:
1. Water and Steam Distillation:
In this method, steam is generated in a field distillation unit by boiling water. The plant material is placed on a grid above the water. The steam passes through the roots, capturing the essential oil, which is then condensed in a water-cooled condenser. The oil and water are collected in separate vessels, allowing for the recovery of various oil fractions based on their densities.
Key Components:
- Still
- Condenser
- Receiver
- Calandria
2. Steam Distillation:
In this process, steam is produced in a separate boiler and directed into a distillation vessel containing the vetiver roots. This method is similar to water and steam distillation but allows control over steam pressure, enabling a more precise distillation process.
Key Components:
- Still
- Condenser
- Receiver
- Boiler
The various features of the two types of distillation of essential oils are given in the table below:
Choosing the Right Distillation Method:
For small-scale farms, water and steam distillation are more economical due to lower equipment costs. However, for large-scale or continuous production, steam distillation is recommended, as it offers better control and efficiency. The quality and yield of essential oil remain similar in both methods.
Harvesting and Preparation for Distillation:
After harvesting, vetiver roots are spread out under shade. Distillation is ideally done within 2–3 days, though it may be delayed up to a week. Before loading the roots into the distillation vessel, they are either sprinkled with water or soaked briefly. Exposure to high temperatures should be avoided to prevent the evaporation of oil fractions. Traditional distillation can take up to 72 hours, but improved steam distillation methods can reduce this time to approximately 20 hours.
Vetiver roots
Distillation Yield and Efficiency:
The yield of vetiver oil depends on several factors, including harvest time, crop age, and distillation method. Roots harvested in high temperatures produce less oil, while crops over two years old have reduced oil content due to root degradation. Proper distillation techniques can yield between 0.8% and 1.2% oil, with improved methods yielding up to 12 kg of oil per ton of roots. The average yield is around 20–25 kg per hectare.
Post-Distillation Care:
After separating the oil from water, special care is needed to extract heavier oil fractions that sink to the bottom. Any remaining water must be removed using a separating funnel, as water can degrade the essential oil. To further purify the oil, it is mixed with 4% anhydrous sodium sulfate to remove moisture before being filtered and stored in air-tight containers made of aluminum, glass, stainless steel, or HDPE. Proper storage in a dark place ensures the longevity of the oil, protecting it from water, air, and sunlight.
Vetiver Oil Quality:
The quality of vetiver oil is determined by its chemical composition, primarily its sesquiterpenoid compounds, which number more than 150. The main components influencing fragrance quality are vetiverols and their derivatives. The carbonyl compounds α-vetivone, β-vetivone, and khusimol are considered the primary markers of oil quality in the perfume industry. For example, South Indian vetiver oil contains 12–17% khusimol, 2–6% α-vetivone, and 1–4% β-vetivone, making it comparable to the highly regarded vetiver oil from Haiti.
Conclusion:
Distillation of vetiver essential oil is a skillful process that requires attention to timing, equipment, and storage to achieve high yields and quality. Whether using traditional or improved methods, understanding the factors influencing oil recovery can help maximize efficiency and maintain the purity of this prized essential oil.
References
- Thwaites, C. (2010) Haitian Vetiver: uprooted? Flavor 35(5):22–23.
- Prakasa Rao, E. V. S., S. Akshata, C. T. Gopinath, N. S. Ravindra, Aparna Hebbar, and Nagendra Prasad (2015). Vetiver Production for Small Farmers in India. Springer International Publishing Switzerland E. Lichtfouse (ed.), Sustainable Agriculture Reviews, 17: 337-354. DOI 10.1007/978-3-319-16742-8_10
- https://stock.adobe.com/in/search?k=%22separating+funnel%22&continue-checkout=1
- Demole, E.P., G.W. Holzner, and M.J. Youssefi, (1995). Malodor formation in alcoholic perfumes containing vetiveryl acetate and vetiver oil. Perf. Flavor 20:35–40.
- V.S.Prakasa Rao, C.T.Gopinath and S.P.S.Khanuja (2008).Environmental, Economic & Equity Aspects of Vetiver in south India. First Indian National Workshop on Vetiver, Kochi, 21-23 February 2008.
Further reading
How to Grow Vetiver for Oil Production
Patchouli cultivation guide – How to grow Patchouli Commercially for oil
Distillation of patchouli for essential oil – Patchouli essential oil extraction
Commercial Cultivation of Sweet Basil (Ocimum basilicum) for oil production
