Determination of the total soluble nitrogen content of malt and beer by the Dumas combustion method: collaborative trial

The determination of the total soluble nitrogen content of malt and beer, b y the Dumas procedure, has jointly been collaboratively tested by the Analy sis Committees of the Institute of Brewing (IOB) and the European Brewery C onvention (EBC). Five samples of beer (range 362 to 1159 mg/l) and five sam ples of malt (range EBC 0.598 to 0.798% m/m (dry basis) and IOB 0.534 to 0. 706% m/m (dry basis)) were distributed to eighteen participating laboratori es for analysis. Precision values were judged to be independent of the mean soluble nitrogen content for malt by both IOB and EBC methodologies. Value s for r(95) and R-95 were 0.047 and 0.136% m/m for EBC laboratory wort and 0.039 and 0.144% m/m for IOB laboratory wort respectively. Precision values for beer were judged to be dependent upon the mean nitrogen content (m) in the case of r(95) and independent of the mean nitrogen content in the case of R-95. Values for r(95) and R-95 were 0.074m and 120 mg/l respectively.