Oud, sometimes called aloes or agar, has been long valued as a scent in the Middle East. It has recently become popular in Europe and North America as well. Because it is rare, in very high demand and difficult to harvest, it is one of the most expensive scent ingredients in the world. It is currently worth about  1.5 times its weight in gold, and is therefore sometimes referred to as liquid gold.

What is Oud?

Oud occurs when the tropical agar tree is infested with a mold  known as Phialophora parasitica. To protect itself from this parasitic mold, the tree produces a special, fragrant resin. This is oud, a time-honored ingredient in perfumes. About 110 pounds of wood from the agar tree are required to create about 3/4 of a cup of oud.

As both agarwood and oud are very high-demand items, the agar tree was recently listed as a potentially threatened species. Currently, the agar tree is grown in southeast Asia, including Bangladesh, and India. Oud is a true "oriental scent."

What Does Oud Smell Like?

Unlike other raw materials, the scent of oud varies widely, based on the age of the wood where it was formed and whether the parastic infection was cultivated or naturally occuring. In general oud is warm and woody, but it can have a smoky or sweet edge as well.

It can be quite strong, so it's not the best  scent to choose if you want to fly "under the radar" at work.

Conclusion

I'm really excited to see the ways in which oud continues to influence western perfume makers. It's a luxurious, mysterious, time-honored aroma, unlike anything else. If you like stronger, more complex scents, I'd recommend adding at least one oud-based cologne to your collection.