In biscuits, buttermilk plays several important roles that affect both flavor and texture. Its natural acidity reacts with baking soda or baking powder, producing carbon dioxide bubbles that help biscuits rise and become light and fluffy.The tangy flavor adds depth, balancing the richness of the fat and the mild sweetness of the dough. Buttermilk also contributes moisture, which helps bind the ingredients and keeps the interior tender, while its proteins and slight thickness improve structure without making the crumb dense.