reduced-fat buttermilk

Reduced-fat buttermilk is a cultured dairy product containing between 0.5% and 2% butterfat by weight, significantly lower than traditional full-fat buttermilk (which contains 3.5–4% butterfat). Originally a byproduct of butter churning, modern buttermilk is produced by adding lactic acid bacteria cultures (typically Lactococcus lactis) to pasteurized milk, which ferments the lactose and creates the characteristic tangy flavor and thick consistency. The fermentation process produces lactic acid, which lowers the pH and gives buttermilk its distinctive sour taste and viscosity, distinguishing it from regular milk despite its lower fat content.

Reduced-fat buttermilk functions as a leavening agent and tenderizer in baking, particularly in pancakes, biscuits, cakes, and quick breads, where its acidity activates baking soda to produce lift and a tender crumb. It is also used in marinades for fried chicken and other poultry, as the lactic acid breaks down proteins while adding moisture and flavor. In beverages, dressings, and sauces, it contributes tang and creaminess with less fat than full-fat variants. Its lower fat content makes it suitable for health-conscious applications while retaining the culinary benefits of traditional buttermilk's acidity and flavor profile.