Aseptic beverage products are prepared by mixing beverage ingredients together. The beverage ingredients include a protein source, such as a milk protein concentrate, and at least one buffering agent, with the at least one buffering agent including baking soda. Preferably, the at least one buffering agent further includes lemon juice concentrate. The pH of the beverage ingredients is adjusted to a level between 6.7 and 7.0 using the at least one buffering agent. The beverage ingredients are then heated to at least 139° C., and the at least one buffering agent prevents precipitation of the protein source during heating. Afterwards, the beverage ingredients are packaged as a plurality of aseptic beverage products.