In short
Guaiacol, 2-methoxyphenol, is a phenol formed when wood is smoked or burned. It has a smoky, medicinal odour and is a key note of wood smoke and peated whisky.
What Guaiacol smells like
Guaiacol is a phenol of wood smoke. A wood-smoke study lists it as clove and vanilla, and a threshold study found it among the most potent smoke phenols — lower in threshold than 4-ethylguaiacol. The Good Scents Company places ortho-guaiacol among phenolic, smoky, spicy, vanilla-like and woody compounds but gives no full profile of its own in the material found. Fraterworks describes an intensely powerful smoky-phenolic opening with a medicinal sharpness that evolves into warm vanilla undertones and a surprising tea-rose floralcy, and suggests it for a smoke note where birch tar would be too powerful.
- Leading note
- Smoky phenol
- Supporting facets
- Clove, vanilla, medicinal
- Faint facets
- Woody
- Character
- Sharp, potent, dry
What makes Guaiacol distinctive
The sweet-phenolic core of wood smoke, with clove and vanilla inside it.
Concentration and dilution
Fraterworks calls it very powerful and suggests diluting it to 10% or even 1%.
How Guaiacol is used
Used in traces for smoky, leather and whisky-like effects, and in smoke flavours.
Typical role: modifier (used in small amounts to change the character of a blend).
How Guaiacol differs from similar materials
- 4-Ethylguaiacol
- 4-Ethylguaiacol is described as smokier and bacon-like, with clove; guaiacol is narrower, clove and vanilla, and more potent. (compared directly by a cited source)
- Cade Oil (Rectified)
- Cade is the whole tar — ash, creosote and resin; guaiacol is one smoky phenol.
- Syringol
- Syringol, its dimethoxy relative, is described as woody, medicinal and drier.
- Birch Tar Oil (Rectified)
- Fraterworks suggests guaiacol for a smoke note where birch tar is too powerful: a single smoky-phenolic molecule with a vanilla and tea-rose side rather than a tarry, leathery whole. (compared directly by a cited source)
- 3,4-Xylenol
- 3,4-Xylenol is drier and earthier, burnt rather than sweet; guaiacol is the sweeter smoke, with clove and vanilla.
An asterisk marks a difference that a cited source states directly. The others compare the published descriptions of each material. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.
Formulation considerations
Powerful and persistent; work from dilution.
Identity and classification
- Type
- Aroma chemical
- Origin
- Occurs in nature
- Odour family
- Leather / Woody
- Note position
- Heart note
- Physical form at room temperature
- Liquid
- Also known as
- 2-Methoxyphenol
- CAS number
- 90-05-1
- Molecular formula
- C7H8O2
- Molecular weight
- 124.14 g/mol
- IUPAC name
- 2-methoxyphenol
The CAS number, formula and molecular weight are taken from PubChem compound 460, whose own record lists this CAS number; checked 19 October 2026.
Safety and compliance
Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. It has a harmonised EU classification (Regulation (EC) No 1272/2008, Annex VI): H302 harmful if swallowed; H315 causes skin irritation; H319 causes serious eye irritation. Companies notifying the ECHA C&L Inventory classify it (1,887 reports): H315 causes skin irritation (99.9% of reports); H319 causes serious eye irritation (99.9% of reports). 1 of the reports find it does not meet the hazard criteria. Unless it is harmonised, this is the notifiers' own classification, not a binding one.
This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.
Materials it works with
-
4-Ethylguaiacol
Aroma chemical · Leather / Spicy — smoky, clove, bacon, phenolic
-
Birch Tar Oil (Rectified)
Essential oil · Leather / Woody — smoky, leathery, tarry, phenolic
-
Cade Oil (Rectified)
Essential oil · Leather / Woody — smoky, tarry, leathery, woody
-
Isobutyl Quinoline
Aroma chemical · Leather / Green — leathery, earthy, green, smoky
Guaiacol is also suggested as a partner on the pages for 3,4-Xylenol, Syringol and Ultravanil.
Used in formulas and accords
Used in 17 published formulas
Guaiacol is an ingredient in 13 perfume formulas and 4 accords in the Formula & Accord Library.
Community formulas
RUŌOD House Originals
Original compositions by RUŌOD House.
Further reading
Questions about Guaiacol
Is Guaiacol natural or synthetic?
The molecule occurs in nature. Commercial Guaiacol may be made by synthesis or obtained from natural sources, so check the supplier's specification if the distinction matters to you.
What is the CAS number of Guaiacol?
90-05-1. It was checked against PubChem on 19 October 2026.
Which published formulas use Guaiacol?
Guaiacol is used in 17 published formulas in the RUŌOD Lab Formula & Accord Library, including Birch Ghost, Burnt Sugar Smoke Accord and Cherry Lacquer. Each is listed with a link under "Used in formulas and accords" on this page.
Sources
- PubChem — compound 460, checked 19 October 2026.
- PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
- Molecules (2025) — wood smoke odorants — published literature.
- Schranz et al. (2017) — odour thresholds of guaiacol derivatives — published literature.
- The Good Scents Company — phenolic odour category — odour database.
- Fraterworks — Guaiacol — distributor's description.
- Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 26 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.