Milkshake Sour is defined by lactose-driven creaminess and, at times, restrained fruit use. The style relies on a soft lactic acidity balanced by milk sugar to create a smooth, rounded mouthfeel, while fruit additions remain integrated rather than frontrunner. Carbonation stays present but appropriately low; the body remains pourable. Milkshake Sour prioritises texture through lactose and balance through acidity, avoiding the heavy viscosity, saturated fruit load, and blended-drink character that define smoothie sours.