Raising agent or leavening agent is a powdery or a liquid ingredient used in raising cakes, breads, puddings, cookies and scones rise. This ingredient gives the right texture and shape to the product being made. The main function of a raising agent is to provide carbon dioxide to the bread or any dough or batter, when heated at a certain temperature.
Yeast: Yeast is a unicellular fungi, which acts as a leavening or raising agent to raise the bread dough, cake dough, and even used to ferment wine and beer. Some of the foods that use yeast for leavening the dough are breads, cakes, and cookies. Yeast is always mixed with warm water, salt, and little flour when it is used for raising the dough.
Beer : Beer is a fermented drink, which is obtained by saccharification of starch and then fermenting the sugar resulting from it. Beer as a leavening agent in food products is used in preparing beer bread. However, with this, baking powder is also used to make it lighter and softer.
Buttermilk: Buttermilk or sourmilk, being acidic in nature helps in raising the dough prepared to make pancakes, muffins, cakes, and cookies.
Baking Powder: Baking powder is a dry raising agent, which increases the volume of the product and also lightens its texture. It acts as a leavening agent by releasing causing dioxide in the batter, which creates bubbles and gets into the acid based reaction. It is used in the preparation of cakes, muffins, American style muffins, scones, and breads, often called as quick breads when they are leavened with baking powder.
Steam: Steam is caused in the batter or dough of a dish when large amounts of eggs, water, milk gets converted into steam when heated in the oven. The steam caused by the heat helps in raising the dough of cakes, muffins, and Yorkshire puddings.
Creamed mixture: Creamed mixture is obtained by mixing the butter with sugar which creates bubbles in the batter. This acts as a leavening agent, however, this can further be made into a better leavening agent by adding baking powder or any other chemical based rising agent. This is commonly used in preparing cookies.