Quick bread is a type of bread that is leavened with a chemical leavening agent, such as baking powder or baking soda, instead of a biological one like yeast or sourdough starter. Quick breads are prepared quickly and reliably, without requiring the time-consuming skilled labor and the climate control needed for traditional yeast breads. They include many cakes, brownies, and cookies, as well as banana bread, pumpkin bread, beer bread, biscuits, cornbread, muffins, pancakes, scones, and soda bread. Quick breads can be made with a variety of ingredients, but almost all have the same basic ingredients: flour, leavening, eggs, fat (butter, margarine, shortening, or oil), and liquid such as milk. The type of bread produced varies based predominantly on the method of mixing, the major flavoring, and the ratio of liquid in the batter. There are two main mixing methods utilized when making quick breads: the muffin mixing method and the biscuit mixing method.