‘Foam-Loving’ Complex Nitrogen Materials in Beer

Complex nitrogen materials with affinity for foam have been separated from beer and characterized by isoelectrophoresis. They represent approximately one third by weight of the total beer complex-nitrogen fraction, they possess properties similar to those of proteins, and as a group they confer foam stability when added to beer media of low inherent stability. The remaining two thirds of the complex-nitrogen fraction, which shows properties atypical of proteins, also shows little affinity for foam. It is concluded that only complex-nitrogen species of high surface activity are very potent foam-stabilizing agents in beer.