Arise! The History of The Chemistry of Cake Making and Why Aair is The Secret Ingredient

As soon as man began to grow grains and cereals, he began to bake. The precursor of cakes were sweetened breads: the Egyptians, Greeks and Romans all made forms of leavened confections which contained honey, fruits, nuts, wine and seeds. As the Roman Empire spread throughout the Mediterranean and Britain from 27 BC to 476 AD, the use of yeast and baking also spread throughout the known world.

The Roman statesman and writer Cato The Elder wrote how important the pastry chef, or pastillarium, was in Roman society, where celebration, carnival and festival cakes and pastries were sold both on the streets and in shops, as well as consumed in private houses and inns. In his works we read about libum (sacrificial cake made with flour), globus apherica (sweet fritters), scibilata (torta), spira (ancient form of pretzel), placenta (cheese cake) and satura (flat cake made with barley, raisins, pine nuts, pomegranate and sweet wine) and it reminds us how ancient cake making is as an art form, and how many guises the modern day cake has been through.

From the Germanic Kugelhopf, to the Welsh Bara Brith, the use of yeast as the leavening agent in cake making was the most popular method of raising cakes well into the 17thCentury, when beaten eggs replaced it as the main method for creating a porous, light mixture. In addition, colonial expansion in Africa and the Caribbean meant that cane sugar was being imported into Britain, its crystalline structure helping to incorporate air into cake mixtures, allowing them to expand, rise and remain spongy and light.

The earliest recipe for a sponge cake mixture was given by Gervase Markham in 1615, although back then cakes were not as we think of them today but rather more like flat, crisp and thin biscuits. It is the higher proportion of fat in modern day cakes, derived mainly from butter or a shortening like margarine, that inhibits the formation of gluten, formed when flour and liquid are mixed. The protein and the starch in the cake batter mix coagulate and gelatinise into a stable foam, thereby giving a more risen, moist, and soft crumb that distinguishes a cake from a sweet bread or a biscuit.

Invented in the USA in the 19thCentury, bicarbonate of soda (NaHCO3) is an alkali that reacts with an acid, normally cream of tartar which is an acid salt, to create carbon dioxide (CO2). When wetted, the two chemicals immediately begin to create bubbles in the mixture, and this needs to be placed immediately in the oven. The heat speeds up the reaction so that more CO2 is created, and this enables the cake to rise, as the volume of the air bubbles expands. It is very important to throw away any out-of-date baking powder, because the drying agent used in the container, normally starch, is not completely effective in stopping the reaction. This means that some of the baking powder’s effect is lost in storage.

It was Eben Norton Horsford, the Rumford Professor of the Application of Sciences to the Useful Arts at Harvard University, who packaged baking powder in metal cans using corn starch as the method of ensuring the powder was kept dry. Rumford Baking Powder is still sold today. Prior to that, in the 1890’s, previous inventors of old-fashioned baking powder, like August Oetker of Germany and Joseph and Cornelius Hoagland, packaged acid and alkaline mixtures in glass bottles and they had a very short shelf life.

My the mid 19thCentury bicarbonate of soda and baking powder replaced yeast in cake making. Many manufacturers handed out cake recipe leaflets so that housewives would know how to bake different cakes, and this led to the proliferation of cake-baking in many households across America and Western Europe, where there is still a very strong cake baking culture.

Bicarbonate of soda cannot make a cake rise on its own, but with the addition of an acid, such as vinegar, buttermilk, yoghurt or lemon juice within the batter mix, the chemical reaction to produce CO2 would work just as well as the addition of cream of tartar. Other important criteria for the successful and even rising of a cake include sieving the flour before mixing, using the correct size of tin and correct lining, the correct oven temperature, positioning the oven rack and cake tin in the centre of the oven, placing the cake in the oven as soon as the batter is mixed and not opening the oven door to reduce the temperature during the baking time.

Four basic methods of cake making came to prominence from the mid 19thCentury onwards.  The most popularly known is the creaming method, where the butter and sugar are mixed together till white and fluffy, incorporating air bubbles which are then increased in number with the addition of beaten eggs. Flour is folded gently with a metal spoon, thereby not opening up the surface area of the cake mix, which would enable trapped air to escape. The baking powder begins releasing carbon dioxide as soon as it enters the mix and once in the oven, as we have seen above, futher CO2 is emitted so that the cake rises to create a soft, spongy cake with a golden top, owing to the caramelisation of proteins.

The rubbing in method consists of rubbing cold butter into flour with the movement of the fingertips, and the sugar, eggs, liquids (such as liqueurs, juices, milk), flavourings (such as vanilla extract or seeds, citrus peel, nuts, candied peel), spices (such as nutmeg, coriander, five spice, ginger, cloves or cardamom) and fruit (such as raisins, dates) are mixed in subsequently. The rubbing in method coats the flour particles in the mix so that the proteins in the flour do not form gluten links when the liquid is added. Gluten linkage is what gives bread its “tougher” texture, as opposed to cake, which should have a lighter texture.

In the melting method the fat, sugar and any liquid are melted together before the eggs, flower and baking powder are added, whereas in the whisking method the eggs are separated and whisked vigorously, distributing tiny air bubbles to be held in the flour mixture, which then expand in the oven.

The Victoria Sandwich Cake is a good example of the creaming method. It is not a true sponge cake, because the eggs are not whisked. It is most closely related to the Pound Cake, an 18thCentury recipe which calls for equal quantities of flour, butter, sugar and eggs in weight.

The rock cake or rock bun made with raisins, dates back to 1860 and is an example of the rubbing in method, producing a craggy, irregular appearance. They are not hard cakes but tend to have a crisp outer layer, with a softer, fruity core. They were commonly eaten with sherry as an accompaniment.

A Parkin is a good example of a cake made using the melting method. Originally from the North of England, melted butter or lard, sugar or molasses, oatmeal and ginger were mixed and baked on the hearth or griddle. The gingerbread cakes could be either thin or thick and were commonly served on Bonfire Night. The whisking method is epitomised by the creation of Genoise sponges, madeleines, boudoir biscuits and Swiss Roll, all of which are very soft, spongy, fluffy, light and pale. Layered or served with cream, jam, custard or melted chocolate (as in Tiramisu, trifle or Genoise layer cakes)  an airy, whisked cake can make the perfect ending to a meal.