The method describes how to determine the iso-α-acids and reduced α-acids in hop products. The method is only suitable for products which only contain a single type of iso-α-acid and reduced α-acid. Isomerized extracts, which contains α-acids and/or β-acids, are to be analyzed according to R-322.01.131 Iso-α-Acids, α-Acids and β-Acids in (Ethanol) Extracts and Isomerized Hop Extracts.
Hop products with isomerized or reduced iso α-acids intended for use in beer brewing or elsewhere in the food industry
Hop products with isomerized or reduced iso α-acids are dissolved with methanol. The bitter acids are separated through reverse phase high-pressure liquid chromatography (RP-HPLC) and isocratic elution. They are then measured at a wavelength of 270 nm.