Phenolic compounds originate in malt and hops. The amount of these compounds present in the finished beer is largely dependent on the technology and equipment used to brew the beer. The structure and size of the molecules determines to what extent they affect the various attributes of the finished beer, such as color, flavor, flavor stability, foam as well as chemical-physical stability. Under less than optimal conditions, for instance given a high concentration of compounds with a proclivity for polymerization, condensation or the presence of air (oxygen), the resultant compounds with the ability to precipitate proteins, possess an undesirable flavor.
Determination of the total polyphenol content
This method is suitable for wort, beer and other beverages
Polyphenols react with ferric iron (Fe3+) in an alkaline solution, forming iron complexes. The complexes created by the reaction yield a brownish color, which is measured spectrophotometrically at 600 nm [2].