The invention relates to a system and method for pasteurizing a liquid product (P) consisting of at least one liquid component that can be pumped, comprising a supply container (6) for making the unpasteurized product available, an inlet line (8a) for conveying the unpasteurized product, a pasteurization circuit (25) for pasteurizing the product (P), and an outlet line (8b) for conveying the pasteurized product. The pasteurization circuit (25) comprises a buffer container (2) for holding the product (P) during a prescribed constant contact time for pasteurization and a fluctuating flow rate of the product (P) through the buffer container (2).