ASBC Methods of Analysis - Malt-8: Protein (N × 6.25)
ASBC Methods of Analysis
Protein (N × 6.25)
This method determines the protein content of malt by two procedures. The first is the Kjeldahl method, which measures total nitrogen in malt that can, after acid digestion, be distilled off as ammonia. If the results are desired as “% protein,” the conventional factor of 6.25 is used to convert nitrogen to protein, notwithstanding the fact that, as barley progresses to malt, to wort, and to beer, “N × 6.25” becomes increasingly less a representation of true protein. The second method measures nitrogen formed during combustion of the sample in pure oxygen (see Barley-7C). Nitrogen values can be converted to protein by multiplying by 6.25.