Investigations are described in which mash and wort samples, collected at various stages of the mashing and wort boiling processes, were analysed for total soluble nitrogen, high molecular weight protein and alpha amino nitrogen. The results show that, since the ratio of total soluble nitrogen to amino nitrogen remains constant from mashing in (when the first samples were taken) to the completion of wort boiling, proteolysis cannot be taking place during that interval and all losses of nitrogenous matter must be due to precipitation. High molecular weight proteins (which are thought to include foam positive proteins) decline in concentration with increasing temperature. It was also found that the sum of the total nitrogen contents of the wort, spent grains and trub equals the total nitrogen content of the malt, confirming the other findings. It proved difficult to determine whether any definite qualitative changes took place, but further investigations, focusing on foam positive proteins and the effects of wort production parameters on beer foam quality, were being planned at the time of writing.
Keywords : composition mash mashing nitrogen content protein wort wort boiling