The main ingredients in sponge cakes are egg, sugar and flour. The addition of air is another key ingredient in the sponge, which gets introduced through the mixing process. In recent years, particularly in the case of sponges produced on a large scale, where shelf life is an important factor, a number of other ingredients have been added such as fats and emulsifying agents. In recipes containing less egg it is usual for baking power to be used to provide additional aeration.
Basic sponge cakes formula:
Air is mechanically beaten into the eggs/sugar mix until a stable foam is produced. The flour is then folded in carefully and baked until the egg and flour proteins coagulate, the starch partially gelatinizes and the cake sets.
Aeration is brought about by the expansion of the air bubbles or the reaction between baking powder and water vapour. During the cooking process., air expands, thus pushing the cake to rise.
Today many sponge cakes are produced by the all-in-one-method using conventional, continuous or high speed mixers. So far, as aeration is concerned artificial chemicals can be used to aid this, such as, baking powder or bicarbonate of soda.
Whisking can be defined as the process of mechanically incorporating air into a mixture by continuous disruption of the surface by a fast moving body. It is only useful to beat air into a mixture if it the mixture is stable enough to hold them through-out the cooking process. However, steps must be adhered to in a recipe, so to not remove air that has been created, for example, over mixing.
Sponge making methods
This is the method whereby the eggs and sugar are whisked together to a stable foam and then the flour is folded in carefully to avoid excess loss of air. The flour must be well sieved in order to remove any lumps and to assist in its easy dispersion throughout the mixture.
This is a modification of the orthodox process whereby the egg whites and yolks are whisked separately, each with a proportion of sugar, blended together and then the sieved flour is blended in. This method is common in high-class mixings where fresh eggs are used. It is particularly suitable for very light sponge mixings, such as is required for Othello’s.
In this method all the ingredients, including the flour, are whisked together with the exception of the bicarbonate of soda, which is dispersed in a small quantity of the total liquid and stirred into the sponge after it has attained full volume. The bicarbonate of soda is the alkaline components of the baking powder, which is virtually being used. The acid component – i.e. cream of tartar is added at stage one. This acidified mix whisks up much better and as the method was first introduced to produce a stable foam when using dried eggs, which on its own will not hold air.
As the name implies, this is a method whereby all the ingredients are mixed together at one stage. In conventional vertical mixers this is a more common method than the delayed soda and produces a reasonable sponge. For good textured sponges it requires the use of an emulsifying agent.
Strictly speaking, this is not a distinct method for making sponge goods, but rather the use of a specially enclosed mixer to allow for the introduction of air during the whisking process. It is merely a different method of adding air and with this type of mixer sponges are made either by the orthodox or all-in-one method.
This again uses the all-in-one method using a different type of machine. All the ingredients are metered continuously into the mixer head together with air, which is fed in at a predetermined rate to produce the desired density of batter.
Again an all-in-one process using a different type of mixing action. The Tweedy/Cressex one-stage process is also used for the manufacture of sponge goods of all types. No modification in the normal all-in-one type of mixing is required. The total mixing time is approximately 1 ½ minutes, a marked saving of time when compared with vertical mixers.