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.
This method describes how to determine the soluble nitrogen content in (Congress) wort according to the Dumas combustion method.
The term soluble nitrogen refers to the quantity of nitrogenous substances, which go into solution under the conditions present during the Congress mash method.
Suitable for all (laboratory) worts
Wort is produced using a laboratory mash method (fine grind) after which the nitrogen content of the wort is determined.
The sample is combusted in a pure oxygen atmosphere at approx. 1000 °C. The resulting mix of gases comes into contact with a CuO/Pt catalyst and is thereby completely oxidized and subsequently freed of all by-products which could potentially interfere with analysis.
After the nitrogen oxides formed in the combustion process are reduced upon contact with tungsten, all nitrogen compounds in the sample are reduced to elemental nitrogen (N2). The elemental nitrogen is then detected by means of a thermal conductivity detector (TCD), the signal of which is quantitatively evaluated by a dedicated integrator.