Guaethol
Guaethol is 2-ethoxyphenol, an aromatic compound of formula C8H10O2 and CAS number 94-71-3, the ethyl homologue of guaiacol in which an ethoxy group sits ortho to a phenolic hydroxyl on the benzene ring. Its odour is smoky and phenolic like guaiacol but noticeably sweeter and more vanilla like, with less of the medicinal edge, which is why flavourists use it where a smoky note has to sit alongside sweet or dairy character without turning harsh.
The pure substance melts near 29 degrees Celsius and boils around 216 degrees Celsius, so it presents as a colourless to pale yellow liquid or a low melting crystalline mass depending on storage temperature. It is only sparingly soluble in water and freely soluble in ethanol, propylene glycol and edible oils, and is normally stocked as a 1 or 10 percent dilution for compounding because it is used at trace levels. The free phenolic hydroxyl makes it prone to oxidation and to darkening on exposure to air and light, so it is filled under nitrogen into light shielded containers and held cool.
We source bulk Guaethol from top China manufacturers for our partners. The manufacturer is in Zhejiang. A smaller requirement can ship in a combined container with other ingredients.
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- Function
- Flavours and Aromas
Specifications
| Item | Specification |
|---|---|
| Appearance | Colourless to pale yellow liquid or crystalline mass |
| Odour | Characteristic sweet smoky phenolic with a vanilla facet |
| Assay by Gas Chromatography | Not less than 98.0 percent |
| Identification | Infrared spectrum conforms to reference |
| Melting Point | 27 to 31 degrees Celsius |
| Refractive Index at 20 degrees Celsius | 1.525 to 1.535 |
| Relative Density at 25 degrees Celsius | 1.080 to 1.100 |
| Solubility | Soluble in ethanol and propylene glycol, sparingly soluble in water |
| Catechol Content | Not more than 0.1 percent |
| Water Content | Not more than 0.2 percent |
| Residue on Ignition | Not more than 0.05 percent |
| Heavy Metals as Pb | Not more than 10 mg per kg |
| Lead | Not more than 1.0 mg per kg |
| Arsenic | Not more than 1.0 mg per kg |
Common Markets Grades
Guaethol is essentially a single specification article. Neat material at 98 to 99 percent minimum assay, made by synthesis and therefore nature identical, accounts for the whole of commercial supply; there is no meaningful natural grade, since isolating it from a botanical or pyrolysis source is not economic at the volumes traded.
The practical grade choice is therefore concentration rather than purity. Neat material is packed under nitrogen in lined containers, and dilutions at 1 or 10 percent in propylene glycol or triacetin are stocked so that a formula calling for a few milligrams can be dispensed accurately. Food grade material is normally specified as conforming to a Food Chemicals Codex style monograph and to the FEMA GRAS listing, with kosher and halal documentation available on request.
Applications
- Smoke flavours, where it supplies a rounder and sweeter phenolic note than guaiacol alone
- Vanilla and vanillin based flavours, adding a woody smoky depth behind the sweet top
- Coffee flavours, reinforcing the roasted phenolic layer
- Caramel, toffee and butterscotch flavours, where a trace lifts the cooked sugar character
- Whisky, rum and brandy flavours, contributing cask and oak notes
- Smoked meat and sausage seasonings applied without a smoking step
- Barbecue and grill sauces, where the phenolic fraction survives cooking
- Savoury and meat flavours as a top note over a Maillard reaction base
- Tobacco and gourmand fragrance accords requiring a sweet smoky facet
- Nut and cocoa flavours, where a small addition deepens the roast
China Manufacturers of Guaethol
Top Guaethol manufacturers in China.
Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.
Regulatory Status
In the United States guaethol carries FEMA GRAS number 2922 and is recognised as a synthetic flavouring substance permitted for use in food under 21 CFR 172.515. Material offered for food use is normally specified against a Food Chemicals Codex style monograph covering assay, refractive index, melting range and heavy metals.
In the European Union guaethol appears in the Union list of authorised flavouring substances maintained under Regulation (EC) No 1334/2008, which permits it for general flavouring use subject to good manufacturing practice, with the substance identified by an FL number within the phenol derivative group. The Council of Europe has listed it in its flavouring inventory. JECFA has evaluated it within the group of phenol and phenol derivative flavouring agents and published a specification for it. Where the material reaches the buyer as a dilution, the carrier solvent must itself be an authorised food ingredient in the jurisdiction of use.
Manufacturing Process
Guaethol is produced by selective mono ethylation of catechol. The common industrial route reacts catechol with an ethylating agent, most often diethyl sulphate or ethyl chloride, in the presence of an alkali such as sodium hydroxide or potassium carbonate in a stirred reactor, with the alkali deprotonating one hydroxyl so that the resulting phenolate is the nucleophile. The reaction is run at partial catechol conversion to keep the mono ether ahead of the diethylated by product. A vapour phase alternative passes catechol and ethanol over a solid acid or metal oxide catalyst in a fixed bed, which avoids the salt stream that the liquid phase route generates.
The crude reaction mass is neutralised and washed with water and dilute acid to remove alkali, salt and unreacted catechol, then separated by fractional distillation under vacuum, since distilling a phenol at atmospheric pressure promotes oxidation and colour formation. Unconverted catechol recovered from the heavies is recycled. The purified cut is polish filtered, assayed by gas chromatography, checked for colour and residual catechol, and filled under nitrogen into light shielded drums.
