4-Ethylguaiacol is an organic compound recognized by chemists, brewers, and food scientists for its distinctive smoky, spicy aroma and impact on the sensory character of various foods and beverages. The molecular formula, C9H12O2, highlights a structure that features an ethyl group attached to a guaiacol unit, which is a methoxyphenol. With a molecular weight of 152.19 g/mol, this chemical appears in multiple forms—ranging from colorless crystalline solid to pale yellowish liquid, depending on purity, storage, and environmental conditions. Under normal ambient conditions, it tends to manifest as solid flakes or crystals, but can also be encountered as a liquid if heated slightly above room temperature.
The core of the 4-Ethylguaiacol molecule centers on a benzene ring substituted with one ethyl group at the para-position, joined by a methoxy group and a hydroxyl group at the ortho and meta positions, respectively. This arrangement drives its solubility, aroma, and chemical reactivity in various processes. The density usually falls near 1.03 g/cm3, a factor to keep in mind when measuring for blends or formulations. Its melting point spans from around 25°C to 30°C, allowing it to shift between solid and liquid depending on handling environment. In powder, crystal, or pearl form, the compound handles easily, but requires attention to proper sealing and moisture control, as phenolic substances often absorb odors and moisture from the air. Upon dissolution, it gives clear solutions with characteristic, intense smell that signals even small concentrations.
In my experience within flavor and fragrance science, 4-Ethylguaiacol delivers spicy, roasted, or smoky notes sought after in artisan food blending, grilling agents, and alcoholic beverage production—especially in aged wines and whiskey, where wild yeast activity or barrel aging leads to its presence. As a raw material, labs use it for research on phenolic compound behavior or for complex synthesis, given its reactive aromatic structure. The HS code typically assigned is 2909509090, fitting with other phenol and polyphenol derivatives, which guides import/export, customs handling, and safety regulation compliance. Although this compound has a strong, recognizable scent, it is managed like many other chemical reagents: keep containers tightly closed, store away from direct solar heat, and avoid contact with eyes and mucous membranes. Inhalation of dust in unventilated areas can bring irritation or headaches. Proper gloves, goggles, and ventilation cut risks dramatically. Disposal follows protocols for organic aromatic compounds, never pouring large volumes directly into wastewater.
In laboratory work, the phenolic hydroxyl reacts with strong bases and forms esters with acid chlorides or anhydrides, enabling the synthesis of derivatives useful for analytical or synthetic chemistry. The molecule resists hydrolysis in neutral water, though prolonged exposure to strong acids or bases changes its structure and destroys aroma. As a raw material, it merges well with other phenolic ingredients for flavor development, and acts as an antioxidant due to its free-phenol group. Its volatility sits between typical solid flavorants and highly volatile liquid compounds, making it persistent during mild heating.
Any warehouse or laboratory managing 4-Ethylguaiacol must pay attention to fire risk. As a phenolic compound, it can sustain combustion under the right (or wrong) circumstances. Fire extinguishers suited for chemical fires (CO2, dry powder) should stand close to stores. For the environment, large spills require neutralization with activated carbon, followed by controlled chemical waste collection. Small-scale use rarely produces significant waste, but it always helps to review local chemical waste regulations, especially for phenolic compounds, which can stress municipal water treatment facilities. Harmful impacts appear with improper use, exposure, or inadequate ventilation, typically leading to headaches, mucous irritation, or rarely, skin sensitization in susceptible workers—risks that well-managed handling, labeling, and personal protection cut nearly to zero.
Many chemical buyers weigh the balance between raw ingredient cost, supply regularity, and regulatory pressure. 4-Ethylguaiacol sits in a group where demand stays steady, largely through applications in specialty flavor and research work rather than bulk commodity processes. Global supply chains require tracking under the right HS code and certificates confirming purity, residual solvent status, and absence of hazardous contaminants. The European Union and United States set thresholds for safe concentration in final food or beverage, reflecting a cautious, evidence-driven approach to aromatic additives that combines industry need with consumer safety. No one in industry escapes the reach of safety datasheets—these shape worker training, labeling, and emergency planning, all critical for safe, cost-effective material use.
