chemical leavening

Chemical leavening causes muffins to rise.

Chemical Leavening

Also Know As: Chemical Leaveners, Leavening Agents, Baking Powder.


What is Chemical Leavening?

Chemical leavening is the combination of sodium bicarbonate (baking soda) and acidic agents with water to generate carbon dioxide gas in controlled volumes and rates. Ammonium bicarbonate or potassium bicarbonate may be used instead of sodium bicarbonate for some applications.

Function

Chemical leavening is an acid + base reaction which results in water, carbon dioxide gas. An example reaction is shown as: NaHCO3 + H + = Na+ + CO2 + H2O. In cakes, cookies, quick breads, biscuits: Chemical leavening is used to aerate the dough or batter rendering it light and porous. The bubbles created by the leavening expand during baking creating the baked product’s crumb structure. Chemical leavening will affect a cake’s pH, which also influences the cake’s crumb color. For example, lowering a cake’s pH will result in a whiter crumb color for a white layer cake.

Composition

Usually consists of an acid and a base; upon reaction, generates carbon dioxide.

Application

For cake use, chemical leavening will be pre-blended with the flour and any other dry, minor ingredients. This blend is added in the final stages of mixing to the cake batter. Chemical leavening will begin to react upon hydration; therefore, timing and the choice of leavening is key to proper cake aeration and gas retention. Leavening will be 0.5 – 1.5% of the cake formulation.
In cookies, leavening follows a similar mixing methods as cake products, although the usage level will be lower, <1%.