The wort analysis methods are written, for example, for wort that is produced using the Congress mash method. These methods may also be applied in the analysis of wort which has been produced using a different mash method, particularly the isothermal 65 °C method. However, the reference values listed in the analysis method for Congress wort are not transferable.
Precipitation with phosphomolybdic acid provides information regarding the nitrogenous substances of medium and high molecular weight present in Congress wort samples. Nitrogenous substances with molecular weights of 2600 daltons and above are precipitated. However, a quantitative elimination of all nitrogenous substances of an equivalent molecular weight does not occur, which indicates specificity toward certain nitrogenous substances.
For the analysis, the reagent phosphomolybdic acid itself is not necessary; a solution of sodium molybdate is sufficient. Through the addition of sulfuric acid, enough phosphoric acid is released from the phosphates present in wort and beer that phosphomolybdic acid is formed.
Applicable for all (laboratory) worts
Medium and high molecular weight proteins are precipitated by phosphomolybdic acid. The nitrogen is determined in the filtrate. Therefore, the results express the amount of low molecular weight proteins.