The Value Of Raising and Leavening in Baked Foods

Raising and leavening agents used to get a rise in cupcakes
Image by Aline Ponce from Pixabay

The purpose of raising and leavening agents in baking is to create a light, airy texture in the finished product. Leavening agents are ingredients that cause the dough or batter to rise by releasing gases, such as carbon dioxide, which get trapped in the dough and create small air pockets. When the baked good is heated, the air pockets expand and the dough or batter rises, resulting in a fluffy, tender texture. Without them, most baked goods would produce flat, rather chewy foods. Many bakers fail to think about using leavening agents when they are producing bread and cookies and then try to work out why their cookies are so flat.

Typical raising agents can be grouped into three main types: these include the chemical agents such as baking powder and baking soda, the biological which is always yeast, and the physical sources such as steam and air. These are especially useful in producing light, airy textures in baked foods. 

Leavening Agents

Leavening is particularly important in bread-making, as it helps the dough to rise and gives the bread its characteristic texture and flavor. Yeast is a common leavening agent in bread-making, as it produces carbon dioxide gas during fermentation, which causes the bread dough to rise. Other leavening agents used in baking include baking powder and baking soda, which release carbon dioxide gas when they come into contact with acidic ingredients, such as buttermilk or vinegar.

Sodium Bicarbonate/Soda

One of the most important leavening agents is soda which is sodium bicarbonate. It is extremely benign as a food ingredient and to be treated as an ally in baking. Soda is bought at the grocers in the baking products aisle as a white crystalline powder. It has a molecular weight of 84.

Sodium bicarbonate is often used when the formulation already contains a certain amount of acid in its make-up. Brown sugar for example is acidic because it contains molasses which has an acidic pH.

Heat during the baking process will also encourage carbon dioxide formation which produces small gas bubbles causing the baking goods to rise.  When heated up to 50ºC, it starts to produce gas which produces the aerated texture in bread for example. By the time of reaching 100ºC, much of it has been converted to sodium carbonate. It is popular because it is so cheap, easily handled and harmless. It doesn’t have a flavour either and can be purchased extremely pure.

Baking Powder

Baking soda only contains a chemical leavening agent which is most often sodium bicarbonate. A baking powder on the other hand contains a leavening agent, a powdered acid with a neutral, inert buffer material.

The use of baking powder incorporates acid such as monocalcium phosphate, sodium aluminum phosphate and the sulphate version, or tartaric acid as well as sodium bicarbonate in some instances. The neutral buffer is another flour, usually cornstarch which serves as a bulking agent.

Active Dry Yeast

The addition of dry yeast to bread mixes is one way of introducing an agent that produces carbon dioxide. It is the classic and well established biological approach to a rise in dough. Some bakers have tried both soda and dried yeast to obtain a rise.

The Use Of Steam

 One of the simplest yet seemingly unexciting processes for leavening bread is to use steam. For any one interested in this, it is just water vapour which is produced when dough is baked and reaches 212 F or 100C and the liquid water trapped in the dough becomes steam.

The volume of steam is 1,500 times that of liquid water so with that type of expansion when a phase change like that occurs we are going to see some serious dough leavening. The effect is magnified too by baking temperatures. I only know of two baked products that rely on steam: choux and puff. As you can tell by steam leavening, the baked dough is mostly flaky and extremely light.

Mechanical Leavening

Mechanical leavening is achieved by the process of creaming. In this technique, sugar crystals are beaten with solid fat such as butter with a spoon or in a mixer. Air is incorporated into the mixture as tiny bubbles. The sugar crystals effectively cut up the butter. A chemical leavening agent such as baking soda is added to help with further raising.  

Leavening can also be achieved through  other mechanical means, such as beating eggs or creaming butter and sugar together, which incorporate air into the dough or batter. In addition, steam can also be used to leaven baked goods, as the steam causes the dough or batter to expand and rise.

In summary then, the purpose of raising and leavening in baking is to create a light, airy texture in the finished product. Leavening agents, such as yeast, baking powder, and baking soda, release gases that get trapped in the dough or batter and create small air pockets that expand when the baked good is heated. Leavening is an essential step in bread-making and is used in a variety of other baked goods to achieve the desired texture and flavor.

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1 Comment

  1. I saw this being mentioned in the IFT question session they have during their annual get together. Must be making an impact! We are interested in leavening too but from a mechanical perspective. Will contact soon.

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