Natural ingredients—flowers, grasses, spices, fruit, wood, roots, resins, balsams, leaves, gums, and animal secretions—as well as resources like alcohol, petrochemicals, coal, and coal tars are used in the manufacture of perfumes. Some plants, such as lily of the valley, do not produce oils naturally. In fact, only about 2,000 of the 250,000 known flowering plant species contain these essential oils. Therefore, synthetic chemicals must be used to re-create the smells of non-oily substances. Synthetics also create original scents not found in nature.
Some perfume ingredients are animal products. For example, castor comes from beavers, musk from male deer, and ambergris from the sperm whale. Animal substances are often used as fixatives that enable perfume to evaporate slowly and emit odors longer. Other fixatives include coal tar, mosses, resins, or synthetic chemicals. Alcohol and sometimes water are used to dilute ingredients in perfumes. It is the ratio of alcohol to scent that determines whether the perfume is "eau de toilette" (toilet water) or cologne.
The Manufacturing Process
1. Before the manufacturing process begins, the initial ingredients must be brought to the manufacturing center. Plant substances are harvested from around the world, often hand-picked for their fragrance. Animal products are obtained by extracting the fatty substances directly from the animal. Aromatic chemicals used in synthetic perfumes are created in the laboratory by perfume chemists.
Oils are extracted from plant substances by several methods: steam distillation, solvent extraction, enfleurage, maceration, and expression.
2. In steam distillation, steam is passed through plant material held in a still, whereby the essential oil turns to gas. This gas is then passed through tubes, cooled, and liquified. Oils can also be extracted by boiling plant substances like flower petals in water instead of steaming them.
3. Under solvent extraction, flowers are put into large rotating tanks or drums and benzene or a petroleum ether is poured over the flowers, extracting the essential oils. The flower parts dissolve in the solvents and leave a waxy material that contains the oil, which is then placed in ethyl alcohol. The oil dissolves in the alcohol and rises. Heat is used to evaporate the alcohol, which once fully burned off, leaves a higher concentration of the perfume oil on the bottom.
4. During enfleurage, flowers are spread on glass sheets coated with grease. The glass sheets are placed between wooden frames in tiers. Then the flowers are removed by hand and changed until the grease has absorbed their fragrance.
5. Maceration is similar to enfleurage except that warmed fats are used to soak up the flower smell. As in solvent extraction, the grease and fats are dissolved in alcohol to obtain the essential oils.
6. Expression is the oldest and least complex method of extraction. By this process, now used in obtaining citrus oils from the rind, the fruit or plant is manually or mechanically pressed until all the oil is squeezed out.
7. Once the perfume oils are collected, they are ready to be blended together according to a formula determined by a master in the field, known as a "nose." It may take as many as 800 different ingredients and several years to develop the special formula for a scent.
After the scent has been created, it is mixed with alcohol. The amount of alcohol in a scent can vary greatly. Most full perfumes are made of about 10-20% perfume oils dissolved in alcohol and a trace of water. Colognes contain approximately 3-5% oil diluted in 80-90% alcohol, with water making up about 10%. Toilet water has the least amount—2% oil in 60-80% alcohol and 20% water.
8 Fine perfume is often aged for several months or even years after it is blended. Following this, a "nose" will once again test the perfume to ensure that the correct scent has been achieved. Each essential oil and perfume has three notes: "Notes de tete," or top notes, "notes de coeur," central or heart notes, and "notes de fond," base notes. Top notes have tangy or citrus-like smells; central notes (aromatic flowers like rose and jasmine) provide body, and base notes (woody fragrances) provide an enduring fragrance. More "notes," of various smells, may be further blended.
Because perfumes depend heavily on harvests of plant substances and the availability of animal products, perfumery can often turn risky. Thousands of flowers are needed to obtain just one pound of essential oils, and if the season's crop is destroyed by disease or adverse weather, perfumeries could be in jeopardy. In addition, consistency is hard to maintain in natural oils. The same species of plant raised in several different areas with slightly different growing conditions may not yield oils with exactly the same scent.
Problems are also encountered in collecting natural animal oils. Many animals once killed for the value of their oils are on the endangered species list and now cannot be hunted. For example, sperm whale products like ambergris have been outlawed since 1977. Also, most animal oils in general are difficult and expensive to extract. Deer musk must come from deer found in Tibet and China; civet cats, bred in Ethiopia, are kept for their fatty gland secretions; beavers from Canada and the former Soviet Union are harvested for their castor.
Synthetic perfumes have allowed perfumers more freedom and stability in their craft, even though natural ingredients are considered more desirable in the very finest perfumes. The use of synthetic perfumes and oils eliminates the need to extract oils from animals and removes the risk of a bad plant harvest, saving much expense and the lives of many animals.
Source : http://www.enotes.com