In short
Sulfurol is a sulphur-containing thiazole found in cooked and fermented foods. JECFA describes its odour as beefy and nutty.
What Sulfurol smells like
JECFA, the joint FAO/WHO committee that evaluates flavouring substances, describes sulfurol as a colourless to pale yellow viscous oily liquid with a beefy, nutty odour that may darken on ageing. Fraterworks describes a creamy, warm, lactonic aroma with subtle roasted undertones and a soft, sweet dairy character.
- Leading note
- Beefy
- Clear facets
- Nutty
- Character
- Savoury
What makes Sulfurol distinctive
A cooked-meat, nutty note — savoury rather than sweet, which sets it apart from the roasted-sweet pyrazines.
Concentration and dilution
Fraterworks sells it pure and at 10% in DPG because of its strength, and advises waiting at least 24 hours between additions.
How Sulfurol is used
Fraterworks uses it to enhance milky accords in gourmand fragrances and to add creaminess to vanilla, coconut and dessert compositions.
Typical role: modifier (used in small amounts to change the character of a blend).
How Sulfurol differs from similar materials
- 4-Methyl-5-vinylthiazole
- Vinyl sulfurol, its vinyl relative, is described as nutty and cocoa-like rather than beefy.
Each difference compares the published descriptions of the two materials. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.
Formulation considerations
May darken as it ages, according to JECFA. Very food-like; work from dilution.
Identity and classification
- Type
- Aroma chemical
- Origin
- Occurs in nature
- Odour family
- Gourmand
- Note position
- Heart to base note
- Physical form at room temperature
- Viscous liquid
- Also known as
- 4-Methyl-5-thiazoleethanol, 4-Methyl-5-(2-hydroxyethyl)thiazole
- CAS number
- 137-00-8
- Molecular formula
- C6H9NOS
- Molecular weight
- 143.21 g/mol
- IUPAC name
- 2-(4-methyl-1,3-thiazol-5-yl)ethanol
The CAS number, formula and molecular weight are taken from PubChem compound 1136, whose own record lists this CAS number; checked 24 October 2026.
Safety and compliance
Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory classify it (424 reports): H315 causes skin irritation (17.2% of reports); H319 causes serious eye irritation (17.2% of reports); H335 may cause respiratory irritation (17% of reports). 350 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
-
2,3,5-Trimethylpyrazine
Aroma chemical · Gourmand — roasted, nutty, cocoa, earthy
-
Furaneol
Aroma chemical · Gourmand / Fruity — strawberry, caramel, jammy, sweet
-
2-Acetylpyrazine
Aroma chemical · Gourmand — popcorn, roasted, nutty, bready
Sulfurol is also suggested as a partner on the pages for 2-Ethyl-4-methylthiazole, 4-Methyl-5-vinylthiazole, Butter CO2 Extract and Difurfuryl Disulfide.
Used in formulas and accords
Used in 8 published formulas
Sulfurol is an ingredient in 1 perfume formula and 7 accords in the Formula & Accord Library.
Further reading
Questions about Sulfurol
Is Sulfurol natural or synthetic?
The molecule occurs in nature. Commercial Sulfurol 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 Sulfurol?
137-00-8. It was checked against PubChem on 24 October 2026.
Which published formulas use Sulfurol?
Sulfurol is used in 8 published formulas in the RUŌOD Lab Formula & Accord Library, including Banana Bread, Cappuccino Accord and Cookies & Cream Accord. Each is listed with a link under "Used in formulas and accords" on this page.
Sources
- PubChem — compound 1136, checked 24 October 2026.
- PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
- PubChem — Sulfurol (CID 1136): JECFA organoleptic description — odour database.
- Fraterworks — Sulfurol (Milky) — 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.