The objective of the study is to show that the theory of information can be used to describe the random process of mixing of granular materials in a multi-ribbon blender. A new form of the entropy criterion estimating the current state of a mixture is proposed, a mathematical model to describe the variations of the informational entropy during the process is developed, and the experimental validation of the model is done for the blending process duration. Based on the experimental measurements the impulse response of blending process of granular material is obtained. (c) 2005 Elsevier B.V. All rights reserved.