What Substance Makes the Cake Soft and Spongy?

Achieving the perfect texture in cakes is all about understanding the key components and how they work. This article explores the ingredients and methods that contribute to a tender and fluffy texture in cakes.

Sponge cakes, as well as other cake batters, typically achieve their soft and spongy texture by incorporating egg foam that is filled with air bubbles. You can create foams by using beaten whole eggs, egg yolks, and egg whites, or by exclusively using egg white foam. 

Some cakes, Chiffon cakes, in particular, rely on both chemical leaveng provided by baking powder and the inclusion of egg foam to achieve their characteristic rise.

The Science Behind Soft and Airy Cakes

The making of sponge cakes and the airiness of the batter depends on the creation of an egg white foam. During the whipping process, egg whites form thin, flexible membranes that capture and retain incoming air particles.

When we beat egg whites with sugar, tiny air pockets, and bubbles emerge within them, causing their volume to expand significantly, often tripling in size. Sugar adds strength to these air pockets’ walls.

The resulting egg white foam, combined with egg yolks and flour, contributes to the formation of the airy dough structure, which solidifies into a soft, sponge-like texture after baking.

Chiffon cakes include baking powder and do not rely solely on whipped egg whites for rising. In this method, the egg whites whipped with sugar are gently mixed into a batter made with egg yolks, oil, water, flour, and part of the sugar.

The Significance of Flour in Cake Texture

In baking, you’ll commonly encounter three types of flour: all-purpose, cake, and bread flour.


The protein content in flour, specifically gluten, plays an essential role in cake texture. Gluten is a protein that, when mixed with liquid and agitated (as in cake batter), forms a network of elastic strands. In bread, this network is desirable for structure and chewiness, but in cakes, we want to minimize gluten development. Therefore, we avoid using bread flour in cake recipes because of its high protein content.

Cake flour, with its lower protein content, helps ensure that the cake remains tender and light by preventing excessive gluten formation. It’s finely milled and is essential in achieving a soft and airy cake crumb.

All-purpose flour is versatile and can be used for a wide range of baked goods, including cakes that include fruits and, as a result, need a stronger structure.

By substituting up to 10% of the flour with wheat starch, we can lower the gluten content, resulting in a softer sponge cake. Sifting the flour before incorporating it into the batter is equally important, as it helps break up clumps, aerates the flour, and ensures an even distribution in the mixture. These steps contribute to the consistency and quality of your cake’s texture.

Cherry cake on a glass plate sprinkled with powder sugar
Chiffon cake with cherries

The Importance of Precise Measuring

To achieve the right cake texture, precision matters, starting with flour measurement. Using a kitchen scale to measure ingredients by weight is the most accurate method. If you’re using measuring cups, be sure to level it off with a flat edge. For more information, you may wish to read my article on the importance of accurate measuring in baking.

To ensure uniform quality in sponge cakes, we use eggs with consistent weights: 1 whole egg weighs 50 g, 1 egg yolk weighs 20 g, and 1 egg white weighs 30 g.


Proper Mixing of Cake Batters

Before you begin the process of whipping the egg white foam, here are a few key considerations:

  • Ensure that all utensils and equipment are clean and free of any residues.
  • You can create the desirable tiny air bubbles through slow whisking.
  • It’s advisable to use eggs at room temperature before whipping.
  • Adding a few drops of vinegar or lemon juice can enhance the gas-binding ability of egg whites, thereby increasing the stiffness of the foam.
  • It’s crucial to whip the egg whites right before use and avoid letting them sit. If they are left standing, they lose their stiffness, collapse, gradually turn liquid, and cannot be whipped again.
  • Make sure no foreign substances, such as egg yolks, flour, or fats, get into the egg whites.

Egg whites should be whipped to form soft peaks, not stiff ones. When egg whites are overwhipped and become stiff, they lose their ability to expand during baking. However, if you whip the whites to soft peaks, they can stretch further during baking and make the cake rise.

When whipping the foam, it’s essential to stop when it reaches a solid yet slightly elastic consistency. If it starts to break into pieces, that’s a sign of overwhipping. Cakes made with overwhipped foam tend to have a weak, dense structure with visible holes.

Martha Bakes Orange Chiffon Cake

When incorporating the egg white foam with other ingredients, do so gently and carefully to prevent damaging the foam during mixing. If the walls of the egg-white bubbles are compromised, the trapped air escapes, resulting in a dense and compact finished product.

This foam structure is then weighed down by other ingredients in the batter, such as egg yolks, fats (like butter, margarine, or oil), ground nuts, and crumbs. It’s crucial to carefully balance these ingredients’ proportions to maintain the batter’s structure.

The more butter or fats you add to the batter, the denser it becomes, and the smaller the air pockets. However, it will be less prone to drying out. While it’s generally best to stick to tried-and-tested recipes, if you choose to experiment, remember to consider these fundamental principles.


Baking and Handling Tips for Cakes

Sponge cakes have a relatively high sugar content and a loose structure. Therefore, it’s best to bake them in a preheated oven, at temperatures not exceeding 320-355°F/160-180°C. Frequent opening of the oven door, especially when the cake is rising, can be harmful and may lead to sinking and a soggy texture.

To check for doneness, gently touch the cake’s surface with your fingertip after about 15 minutes. If it’s soft, or your fingerprint remains, it indicates that it’s undercooked. A well-baked cake will have a springy surface.

When baking sponge cakes in cake pans, it’s important to prepare the pan correctly. Grease the bottom of the pan and then either dust it with flour or line it with parchment paper. However, avoid greasing the sides of the pan. Chiffon and angel food cakes should be baked in ungreased pans.

A sponge cake in a round mold inside the oven.
Sponge cake batter in the oven

To maintain the volume of these cakes, cool them by placing the pans upside down, and propping up the edges to keep the top of the cake elevated. Once cooled, gently release the cake from the pan by running a knife or spatula along the sides and carefully removing it.

If you’re baking sponge cake sheets, pour the batter onto a tray that has been greased and floured or covered with parchment paper. Use a spatula to evenly spread the batter. For shaping sponge cake dough, you can use a piping bag, such as when making ladyfingers. In this case, use a tray that is also greased and floured or covered with parchment paper.

Cake Batter Classification

Cake batters can be categorized based on how they are made and what ingredients they contain.


When it comes to their preparation method, we have cake batters made using both cold and hot methods. Cold-prepared batters have numerous large air bubbles, making them prone to drying out faster. In contrast, batters prepared using the hot method, also known as egg foam batter, contain fewer air bubbles and tend to retain moisture better.

Cakes can be categorized as either heavy or light, depending on the ingredients used in their preparation.

Light batters contain little to no fat. Their batter is filled with many large air bubbles, making them voluminous relative to their weight. They tend to dry out quickly, so it’s essential to store them carefully in a cool place.

Heavy batters contain more egg yolks and fats compared to egg whites. They may also include a larger quantity of ground nuts. While they have a smaller volume in relation to their weight, they retain moisture longer. Heavy sponge cakes are more long-lasting compared to their light counterparts.

Final Thoughts

In conclusion, achieving the perfect soft and spongy texture in cakes is indeed a science, and it hinges on a few key ingredients and precise techniques.

Egg foam plays a crucial role in giving cakes their airy structure. The choice of flour and the proper measurement of ingredients impact the cake’s tenderness. Finally, baking at the right temperature and avoiding unnecessary interruptions in the oven is vital for that perfect cake.


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