glasses buttermilk

Buttermilk is a tangy dairy liquid produced as a byproduct of butter churning, though modern commercial buttermilk is cultured from low-fat milk inoculated with lactic acid bacteria (typically Lactococcus lactis). Traditional buttermilk from butter-making is thin and watery with small flecks of butter; cultured buttermilk, the predominant commercial form, is thick, sour, and viscous with a pH of 4.4–4.8, resulting from lactose fermentation into lactic acid. The flavor is distinctly tangy and slightly acidic, with subtle dairy undertones.

Buttermilk is available in low-fat or fat-free versions in most commercial contexts. Its acidity and protein content give it unique functional properties in baking and cooking. The liquid ranges from pale cream to off-white in color depending on production methods and feed of dairy animals.

Buttermilk is essential in baking, where its acidity reacts with baking soda to produce carbon dioxide and lift in quick breads, pancakes, waffles, biscuits, and cakes. It is also used in marinades for poultry and meat, where its acidity and lactic enzymes tenderize protein fibers. In dressings, sauces, and frozen desserts, buttermilk contributes tangy flavor and creamy texture. It appears in Irish, Southern American, and Indian cuisines. As a substitute for regular milk or cream in many applications, buttermilk adds depth and reduces the need for additional leavening agents.