Aromatic alcohols are compounds which exhibit a strong sensory influence on beer. This is especially true of some top-fermented beers with the pronounced aroma of guaiacol. Phenolcarboxylic acids are precursors of these substances and, in fact, possess antioxidative properties.
4-Vinylguaiacol and 4-vinylphenol are derivatives of ferulic acid and coumaric acid, respectively. Both substances appear in higher concentrations in Southern German wheat beers (Weissbier). 4-Vinyl guaiacol is considered an indicator substance.
4-Vinylguaiacol and 4-vinylphenol are compounds that play an important role in beer, especially in wheat beer and pale lager. These compounds are produced exclusively by POF-positive yeasts (phenol-off-flavor). While 4-vinylguaiacol is desirable in wheat beer and provides the characteristic spicy and clove aromas, both compounds are undesirable in pale lager beer and are considered off-flavors. These off-flavors can be caused by contamination with foreign yeasts and various lactobacilli, which has a negative impact on the quality and taste of the beer.
Determination of the aromatic alcohols guaiacol, tryptophol, 4-ethyl guaiacol, 4-vinyl guaiacol, eugenol, tyrosol, 4-ethylphenol, 2-phenylethanol in beer
The method is suitable for beer brewed to any original gravity or to any alcohol content.
The aromatic alcohols in beer are isolated using solid-phase extraction and are detected using gas chromatography-mass spectrometry.