4-Ethylphenol

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4-Ethylphenol^[1]

Other names	p-Ethylphenol 1-Ethyl-4-hydroxybenzene 1-Hydroxy-4-ethylbenzene 4-hydroxyphenylethane
Identifiers
CAS number	[123-07-9]
SMILES	CCC1=CC=C(C=C1)O
Properties
Molecular formula	C₈H₁₀O
Molar mass	122.16 g/mol
Appearance	White solid
Melting point	42-45 °C
Boiling point	218 °C
Hazards
EU classification	Xi
NFPA 704	1 2 0
S-phrases	S7/9, S26, S36/37/39, S45
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

4-Ethylphenol, often abbreviated to 4-EP is a phenolic compound with the molecular formula C₈H₁₀O. In wine and beer it is produced by the spoilage yeast Brettanomyces. When it reaches concentrations greater than the sensory threshold (140µg/L) it can give the wine aromas described as barnyard, medicinal, band-aids, and mousy. In certain Belgian beer styles, a high 4-EP level may be desirable; however, very high levels of the compound in wine can render it undrinkable. The level of 4-ethylphenol is roughly proportional to Brettanomyces concentration and activity, and can therefore be used as an indicator of the yeast's presence. There are significant differences between strains of Brettanomyces in their ability to produce 4-Ethyl Phenol.

1 Biochemistry
2 See also
3 References
4 External links

[edit] Biochemistry

4-Ethylphenol is produced from the precursor p-coumaric acid. Brettanomyces converts this to 4-vinylphenol via the enzyme cinnamate decarboxylase.^[2] 4-Vinylphenol is further reduced to 4-ethylphenol by the enzyme vinyl phenol reductase. Coumaric acid is sometimes added to microbiological media, enabling the positive identification of Brettanomyces by smell.