Water intended for use in beer brewing as well as in the production of other foods
Steam-volatile phenols form by bonding with diazotized p-nitroaniline azo dyes; the intensity of the resultant color is measured photometrically following extraction with n-butanol.
The intensity of the color, based on a saturation threshold of phenol of 100 %, is as follows:
phenol 100 % m-xylenol 52 %
o-cresol 147 % p-xylenol 92 %
m-cresol 120 % guaiacol 165 %
p-cresol 21 % pyrocatechol 29 %
o-xylenol 16 % α-naphthol 23 %
Determination of 4-vinylguaiacol and 4-vinylphenol in beer
The method is suitable for beer brewed to all ranges of original gravity and alcohol content.
Analysis was performed using isocratic HPLC on a Spherisorb separation column with UV detection at 260 nm.
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.
This method is suitable for (bottom-fermented) beer and beverages.
The fraction of phenols extracted using steam are converted to color complex using 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (4-aminophenazone) in an alkaline medium and through oxidation with potassium ferrocyanide (III), which can be measured spectrophotometrically after extraction with chloroform (fig. 1).
This method describes how the protein content in adjuncts is determined.
This method describes how the protein content in adjuncts is determined.