Quick bread leavening agents include a weak base, such as baking soda (sodium bicarbonate) plus a weak acid, such as cream of tartar, lemon juice, or cultured buttermilk, to create an acid–base reaction that releases carbon dioxide. (Quick bread leavened specifically with baking soda is often called "soda bread".) Baking powder contains both an acid and a base in dry powdered form, and simply needs a liquid medium in which to react. Other alternative leavening agents are egg whites mechanically beaten to form stiff peaks, as in the case of many waffle recipes, or steam, in the case of cream puffs. Nevertheless,
Old-fashioned doughnut invented, but this very likely occurred "after" the cake doughnut was invented. Prior to circa 1829, doughnuts were typically the yeast-risen variety in the U.S. Circa the 1830s, the leaveners baking soda and baking powder began to be available to U.S. consumers, which is around the same time that cake doughnut recipes first appeared in U.S. cookbooks. Primary ingredients in an old-fashioned doughnut include flour, sugar, eggs, sour cream or buttermilk, and leavening agents such as baking powder or baking soda. Additional ingredients may include milk, butter, vanilla extract and salt. The use of buttermilk or sour cream may impart