Soda bread (Irish: arán sóide, Scots: fardel, Serbian: česnica/чесница) is a variety of quick bread traditionally made in a variety of cuisines in which sodium bicarbonate (otherwise known as baking soda) is used as a leavening agent instead of the more common yeast. The ingredients of traditional soda bread are flour, bread soda, salt, and buttermilk. The buttermilk in the dough contains lactic acid, which reacts with the baking soda to form tiny bubbles of carbon dioxide.