Top to Base (monoterpene-dominated head, diterpene-resinous tail)
Botanical
Various (Boswellia, Commiphora, Styrax)
Appearance
Colorless to pale yellow clear liquid (essential oil)
Odor Strength
High
Producing Countries
Somalia, Ethiopia (B. carterii, B. papyrifera), Oman, Yemen (B. sacra), India (B. serrata)
Pyramid
Base
Terpenic, bright, unexpectedly citrus for a resin. Olibanum smells like the inside of a stone church at dawn — cold mineral air crossed with lemon peel and warm dust from the censer.
Opens with a citrus-peppery flash — alph a-pinene creating a piney transparency that is startlingly fresh for a res in. Brighter and more terpenic than myrrh, drier and less sweet than benzo in, more mineral than labdanum. With in an hour the monoterpenes lift off and the balsamic-resinous heart emerges: warm, faintly smoky, with a papery dryness. On skin it reads clean rather than cloying. The late dry-down carries a particular waxy, churchlike quality attributed to 2-octylcyclopropyl-1-carboxylic acids — a cold-stone persistence that no synthetic has fully replicated.
Evolution over time
Immediately
Immediately
Bright, terpenic, citrus-peppery. Alpha-pinene and alpha-thujene dominate — a piney, almost lemon-rind transparency that belies the resin's heavy appearance.
After a few hours
After a few hours
The volatile monoterpenes dissipate. Warm, balsamic, faintly smoky — incensole and incensole acetate assert the resinous heart. A papery dryness replaces the initial brightness.
After a few days
After a few days
Dry, waxy, faintly sweet. The characteristic churchlike endnote persists — a cold-stone, dusty warmth attributed to 2-octylcyclopropyl-1-carboxylic acids. Clean rather than heavy.
The Full Story
Incense in perfumery means olibanum: the oleo-gum-resin tapped from Boswellia trees (family Burseraceae). Harvesters score the bark with a mingaf — a broad-bladed scraping tool — and return weeks later to collect the hardened tears. The principal commercial species are B. carterii (Somalia, Ethiopia), B. sacra (Oman, Yemen), B. serrata (India), and B. papyrifera (Sudan, Ethiopia). Despite periodic attempts to synonymise B. carterii and B. sacra, chiral GC-MS analysis shows distinct enantiomeric ratios of alpha-pinene between the two, supporting their separation as individual species.
Steam distillation of the dried tears yields an essential oil (5–10% depending on species) dominated by monoterpenes: alpha-pinene ranges from 2% to 65% across commercial samples; alpha-thujene from 0.3% to 52%. These light terpenes account for the oil's surprising top-note freshness — lemony, peppery, piney — that contradicts the popular image of incense as a heavy, smoky material. The heavier fractions include the cembranoid diterpenes incensole (CAS 22419-74-5) and incensole acetate (CAS 34701-53-6), which contribute the warm, balsamic body. A critical factual point: boswellic acids — the triterpenoids associated with Boswellia's medicinal reputation — are non-volatile (molecular weight ~470) and cannot survive steam distillation. They are absent from the essential oil. Only CO2 supercritical extraction or solvent extraction captures these heavier compounds.
Two highly potent odorants identified via GC-olfactometry, the 2-octylcyclopropyl-1-carboxylic acids, are responsible for the characteristic 'old church' endnote of frankincense — that dry, papery, slightly waxy persistence. CO2 extraction produces a rounder, more complete profile than steam distillation, capturing both the terpenic head and the resinoid tail. Solvent extraction yields an absolute. The resinoid, obtained by hydrocarbon solvent extraction of the crude gum, is darker and more tenacious.
The incense accord runs through Albâtre Sépia, built on olibanum resin and fossil amber, and surfaces again in Gravitas Capitale as a smoky counterpoint to citron and wet asphalt.
Incensole acetate, a cembranoid diterpene specific to Boswellia resin, was demonstrated in a 2008 study by Moussaieff et al. (The FASEB Journal, 22(8):3024-34) to activate TRPV3 ion channels in mouse brains, producing anxiolytic and antidepressant-like effects. The same effect was absent in TRPV3-knockout mice, confirming the mechanism. TRPV3 channels are normally involved in warm-temperature sensing — a possible neurochemical basis for the calming effect historically attributed to burning frankincense in religious settings.
Extraction & Chemistry
Extraction method: Steam distillation of dried Boswellia resin tears yields the essential oil: 5–6% from B. carterii, up to 9–10% from B. sacra, approximately 2% from B. frereana. The oil is approximately 75% monoterpenes, with alpha-pinene and alpha-thujene dominant but in highly variable ratios depending on species, chemotype, and terroir. CO2 supercritical extraction captures a broader molecular range including the heavier diterpenes (incensole, incensole acetate) and — unlike steam distillation — the non-volatile boswellic acids (MW ~470), producing a rounder, more complete olfactory profile. Solvent extraction yields an absolute. Hydrocarbon solvent extraction of the crude oleo-gum-resin produces a darker, more tenacious resinoid. Principal commercial species: B. carterii (Somalia, Ethiopia), B. sacra (Oman, Yemen), B. serrata (India, CAS 97952-72-2), B. papyrifera (Sudan, Ethiopia).
Molecular Formula
C10H16 (alpha-Pinene, ~60%), C20H34O (Incensole acetate, key base component)
CAS Number
8016-36-2 (essential oil, B. carterii) · 97952-72-2 (essential oil, B. serrata) · 8050-07-5 (resinoid/gum)
Botanical Name
Various (Boswellia, Commiphora, Styrax)
IFRA Status
Restricted: up to 8% in fragrance concentrate (TGSC data for CAS 8016-36-2). Restricted components include carvone (0.3%), alpha-thujone (0.1%), (+)-isothujone (0.4%).
Synonyms
ENCENS · OLIBANUM · CHURCH INCENSE · KO · BAKHOOR
Physical Properties
Odor Strength
High
Lasting Power
188 hours @ 100% (TGSC data)
Appearance
Colorless to pale yellow clear liquid (essential oil)
Boiling Point
137–141 °C @ 760 mm Hg
Flash Point
96 °F / 35.56 °C (TCC)
Specific Gravity
0.855 to 0.880 @ 25.00 °C (essential oil, B. carterii)
Refractive Index
1.466 to 1.477 @ 20.00 °C
In Perfumery
Olibanum is one of few natural materials that spans from top to base in a single compositi on. The monoterpene-rich head (alph a-pinene, alph a-thujene) provides a citrusy, peppery lift; the diterpene body (incensole, incensole acetate) anchors the dry-down with balsamic warmth. This dual character makes it structurally adaptable across fragrance families. In ambers and ambers, it supplies the sacral, smoky-resinous quality. In chypre constructions, it can extend or partially substitute oakmoss. In fresh-incense compositions — a category that has expanded significantly since the early 2000s — the essential oil's terpenic top is foregrounded against clean woods and citrus. CO2 extract is preferred when the full resinous arc is needed; steam-distilled oil when the bright, citrusy opening matters more. The resinoid is a fixative, adding tenacity without the volatility of the essential oil. No single synthetic molecule replicates olibanum's full profile, though various incense accords are built using combinations of Iso E Super, Cashmeran, and terpenic isolates.
