The method describes how to determine the iso-α-acids, α-acids and β-acids in hop extracts and isomerized extracts by means of high-pressure liquid chromatography.
Hop extract and isomerized hop extract intended for use in beer brewing or elsewhere in the food industry
Hop extracts and isomerized hop extracts are dissolved in methanol. The iso-α-acids, α-acids and β-acids are separated using hig-pressure liquid chromatography (HPLC) with gradient elution and measured spectrophotometrically at a wavelength of 270 nm (iso-α-acids) and 314 nm (α-acids and β-acids).
Determination of xanthohumol and isoxanthohumol
All beers, beer-based beverages, wort, ethanol extracts, CO2 spent hops and xanthohumol products
Xanthohumol and isoxanthohumol are dissolved with acetonitrile from the sample and following separation, are determined using a Nucleodur C18 column and UV detection.
The method is suitable for beers of all original wort ranges and alcohol contents.
Volatile compounds in beer are concentrated through distillation and the distillate is quantitatively determined by direct injection into a gas chromatograph. The linearity of the detector and the determination of the concentrations of analytes in the sample are achieved by using multiple concentration levels within the relevant range and through evaluation of the relative area under the peaks.
This method is suitable for beers exhibiting all ranges of original gravity and alcohol concentrations.
The method is suitable for beer brewed to any original gravity or to any alcohol content.
Volatile compounds in beer are concentrated through distillation and extracted with dichloromethane. The solvent phase is analyzed with a gas chromatograph. The linearity of the detector and the determination of the concentrations of analytes in the sample are achieved by using multiple concentration levels within the relevant range and through evaluation of the relative area under the peaks.
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.
A known quantity of an internal standard (n-propanol) is added to the sample, if necessary after dilution.
The sample is equilibrated at a certain temperature in a headspace vial and part of the headspace is injected into a gas chromatograph.
The ethanol contained is separated on a polar gas chromatography column and detected with a flame ionization detector (FID).
The ethanol concentration in % vol. is calculated from the ratio of the area of the ethanol peak to the area of the internal standard (n-propanol) with the ratios of the same peaks determined when analyzing standards with known ethanol concentrations.