European Brewery Convention: Analysis Committee Sub-Committee on Analysis of Hops and Extracts Methods of Analysis of Hop Extracts

Abstract

For the conductometric analysis of hop extracts the method described by Bishop,6 is satisfactory provided the extract is composed entirely of resins; extracts which contain additional water‐soluble material should be analysed by an abbreviated Wöllmer technique. For isomerized extracts a qualitative examination should first be made, either by paper‐strip chromatography or by thin‐layer chromatography. A rapid counter‐current distribution procedure is suitable for the analysis of isomerized extracts: the modified Rigby & Bethune method22 is appropriate only with extracts which are known to be free from α and β acids.