This method describes how the protein content in malting barley is determined. Protein plays an essential role in the production of beer. Barley with a high protein content is more difficult to malt and leads to greater malting losses. Barley with a low amount of protein is preferable, especially for beers light in color. As the protein content of barley increases, its extract content decreases.
The nitrogen/raw protein content of barley intended for the production of brewing malt must be determined in advance.
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.