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,
Pullman loaf pans used to create the square loaves, square tin pans existed long before the railroad company. European breadmakers began using the pans in the early 18th century to minimize crust. However, the loaves were selected by Pullman for use on his trains. Three Pullman loaves occupied the same space as two standard round-topped loaves, thus maximizing the use of space in the small Pullman kitchen. Pullman loaf The pullman loaf, sometimes called the "sandwich loaf" or "pan bread", is a type of bread made with white flour and baked in a long, narrow, lidded pan. The French term for this