A methodology has been developed in order to achieve peak utility load reduction in batch processes operated periodically and under uncertainty. Based on a combination of computer simulation and an analytically based approach, the former with the help of the BATCHES simulator, this methodology has been applied while following the general objective of modelling and optimizing the brewhouses of an industrial brewery. The steam consumption profiles in these brewhouses exhibit a very irregular behaviour with some demand peaks of very short duration which greatly exceed the average demand. The use of the presented methodology has enabled us to suggest a series of measures resulting in a considerable reduction of the steam consumption peaks. These measures are : a better standardization of the equipment, the choice of an optimized production schedule and the acceptance of a voluntary limitation of the steam availability level. From the most unfavourable situation to the most favourable encountered in our study, the global reduction amounts to 55%.