Agarwood (Oudh)

Agarwood is reputed to be the most expensive wood in the world. There are many names for the resinous, fragrant heartwood produced primarily by trees in the genus Aquilaria. Most commonly, the resin is known as agarwood, aloeswood, eaglewood, gaharu, agalocha or oudh (In Arabic).

                Agarwood has been used to make high quality incense since centuries. The Chinese describe its smell as "a sweet, deep but balanced fragrance" and use it in religious and festive celebrations, and so do Arabian, Indian and Japanese people. Agarwood is also part of many traditional pharmacopoeias, dating back to medieval times and Chinese doctors still prescribe it for colds and disgestion problem. Oil extracted from agarwood is used in Arabian countries as a perfume.

                 Agarwood is a resinous heartwood that occurs in trees belonging to the species of Aquilaria, Aetoxylon (A.symeatalum) and Gonystylus genus of Thymelaeceae family. However, species of the genus Aquilaria are mostly known for the production of agarwood - it's a fast growing, evergreen tree.

 

                Agarwood or oudh forms as a reaction to fungal or bacterial attack. Trees, ocassionally become infected with a parasite mould secrete a fragrant, protective oil into wounded areas (roots, branches or sections of the trunk), which gradually become harder and dark brown to black. The heartwood (central part of a tree, which is darker in color than the sapwood) is relatively light and pale color before infection. Normally harvesters would cut only the infected parts in the hope that the tree would produce more of this resinous wood.

                                                 

                                  Aquilaria species that produce agarwood are found throughout Asia, while occur naturally in South and Southeast Asia. The Indian sub-continent was the main source of agarwood for many centuries but as trees became scarce in the middle of the twentieth century, extraction intensified in Indochina. Later on it was extended to Indonesia and Malaysia. Today Agarwood plantations exist in a number of countries, including Bangladesh, Bhutan, India, Laos, Myanmar, Papua New Guinea, Thailand and Vietnam.

It can grow on a wide range of soils, including poor sandy soil. Seedlings of most species establish best in shady, moist conditions, but large adult trees sometimes become emergent in the forest and can withstand full sun. Some species can be found growing on steep, rocky, exposed slopes, and in regions that experience a hot, dry season. The trees grow to 6-20 m tall.

The leaves are alternate, 5-11 cm long and 2-4 cm broad, with a short acuminate apex and an entire margin. The flowers are yellowish-green, produced in an umbel, the fruit is a woody capsule 2.5-3 cm long. At least fifteen species of Aquilaria trees are known to produce Agarwood.Aquillaria Malacenensis is considered to be the queen of Indonesian oudh. This tree can grow about 40 M or 131.23 ft in height with its diameter 80 cm. It is the best producer of agarwood resin and oil in Indonesia.

Agarwood is exported in various forms (wood chips, powder, oil and as finished products such as perfumes, incense and medicines), and the main importers are countries in the Middle and Far East - in particular the United Arab Emirates and Saudi Arabia (where agarwood is known as oudh), as well as Hong Kong, Taiwan and Japan.

EXTRACTION METHOD

   There are three methods through which agarwood oil is distilled namely, hydro-distillation, steam distillation and super critical CO2 extraction. However, the most common methods of distillation are hydro-distillation and steam distillation. Another thing that has its mark on the distillation of the oil is the age of the tree. Older trees have a higher resin content and just like a wine, old resin gets better with age. Speaking of the grading of agarwood oil, the best quality oil comes out from first distillation and after this the wood undergoes for second distillation and hence, it is graded accordingly the number of times it is cooked.

Oil coming from steam distillation is said to lack the three-dimensional smoky quality which comes from hydro-distilled oil. In both methods, after the oil has been distilled, it is filtered, sunned, and aged for a while. The more the oil aged, the better it will smell.

When is it needed to develop synthetic substitutes?

Development of synthetic substitutes usually arises when sustainable supplies of the natural product are not available and are expensive at the same time. Since, Agarwood cannot be synthesized, chemical substitutes are already available for perfume these are cheap and constitute the least profitable end of the market. In addition, these products do not come even close in mimicking the natural product. The major chemical components responsible for the characteristic scent of Agarwood products, sesquiterpenes, can in principle be synthesized. However, these are very complicated structures that will be extremely expensive to synthesize, which makes it commercially completely unattractive.

So the major difference in fragrances of oudh oil and synthetic oudh can be distinguished easily. Oudh smells heavenly, woody and balsamic and surrounds a warm aura of bitter sweet and woody nuance. Whereas, synthetic oudh smells plain woody, leathry and lacks that warm balsmic aura.