Abstract Increasing demands for economical, efficient, and high-production output rates require better control on processing methods in the factory. Good processing depends very much upon the uniformity of materials at each stage of the operation. The use of modern equipment and deliberate efforts to make the best use of the materials have narrowed the range of acceptable variations in material properties. Therefore, an instrument is needed which, in a very short period of time, will accurately detect deviations in uniformity. The dynamic stress relaxometer (DSR) described in this paper is an instrument which fulfills these needs. Another aspect of processability which also causes great concern is the need to change some ingredient in the recipe. Variations in the ingredient properties, which may be within specifications, sometimes result in large variations in the final product because of their complex interactions. Therefore, it is important that variations in the ingredients, as well as the final compounds, be detected quickly and satisfactorily so that necessary modifications in the recipe or procedure can be made without delay. The DSR has proven to be a useful tool allowing production personnel to make discriminating decisions effectively in our hose plant. The DSR has been used successfully over the last four years to determine whether the Banbury mixing and milling of the compounds were acceptable for processing through a cold-feed extruder.