Abstract: A method is described for controlling the cooking degree of pulp during pulp digestion and for analyzing cooking chemical composition and -concentration before and during cooking operation. The method is based on the continuous or discontinuous monitoring of the IR spectroscopical behavior of the cooking liquor. Evaluated IR-spectal data of cooking liquor samples are correlated with analytical data of the cooking liquor on the one hand and the resulting pulp on the other hand by means of adequate mathematical/statistical methods. A feedback of analytical data is performed to improve the statistical relevance of the method. The invention provides a method for cooking control which is much more accurate and faster than existing control methods.