Frankincense, also known as olibanum, is an aromatic resin valued for thousands of years. It has historical significance, used in perfumes, incense, and traditional practices across various cultures. This substance is widely known in its essential oil form, offering a unique woody, spicy, and sometimes citrusy aroma.
The Source: Tree Resin
Frankincense essential oil is derived from the hardened resin, or “sap,” that exudes from trees belonging to the Boswellia genus. This resin appears as milky white droplets when first released. As it dries and hardens upon exposure to air, it forms solid, translucent pieces often referred to as “tears” or “lumps.” These tears can vary in color from milky white to yellow, amber, or even brownish hues, with lighter colors often indicating higher quality. It is this gum-resin, not the wood, leaves, or flowers of the Boswellia tree, that contains the volatile compounds necessary for producing the essential oil.
Harvesting the Resin
The traditional method for collecting frankincense resin is known as “tapping” or “stripping.” This involves making shallow incisions into the bark of the Boswellia tree. Once cut, the tree naturally produces a milky sap that bleeds out onto the surface, hardening into resin tears over days or weeks. Harvesters typically return to collect the hardened crystals, often using a small axe. Multiple taps may be made over time, and sometimes the initial tears are discarded.
From Resin to Oil: The Distillation Process
Once harvested, the collected frankincense resin is transformed into essential oil primarily through steam distillation. The resin tears are first cleaned and often crushed into smaller pieces. These prepared resin pieces are then placed into a still, where steam is introduced. The steam passes through the resin, carrying the volatile aromatic compounds with it.
This mixture of steam and aromatic compounds then moves into a cooling system, or condenser, where it condenses back into liquid form. The resulting liquid is a mixture of water and essential oil. Since the essential oil is less dense than water, it naturally separates and floats on top, allowing for its collection. This method extracts the oil.
Varieties of Frankincense and Their Sources
Frankincense essential oil can be sourced from various species of Boswellia trees, each contributing unique characteristics to the final oil. Notable species include Boswellia sacra, Boswellia carterii, Boswellia frereana, and Boswellia serrata. Boswellia sacra is found in Oman and Yemen, as well as parts of Somalia and Ethiopia. Boswellia carterii is found in Somalia.
Boswellia frereana is native to northern Somalia. Boswellia serrata, known as Indian frankincense, is found in India and parts of the Middle East and Northern Africa. While all these species yield resin, their chemical compositions and aromatic profiles can vary.