Abstract: Rubber is made by mixing the rubber ingredients at elevated temperature in rubber mixing equipment to obtain a mixed rubber compound. The mixed rubber compound is cryogenically ground into a powder by the application of a cryogenic material into the grinder. A further ingredient is added to the mixed rubber compound powder in a mixer while the further ingredient and mixed rubber compound are in a dry condition to obtain a resulting mixture which is later vulcanized. In one embodiment the further ingredient is fragile ingredients.