Food glorious food! Cakes cakes and more cakes! These sweet creations have had people drooling for centuries. There are many variations from rich chocolate to fruit and nut, covered in buttercream or marzipan, stuffed with jam or cream, the choices are almost endless. They’re perfect for big celebrations or just a chilled out half hour with a cup of coffee. But how on earth do they actually work? How can butter, sugar, flour, eggs and baking powder combine to make a delicate mouth-watering sponge?
Well science magic anyway. Each key ingredient has its own special role, without which the cake would collapse. The major ingredients need to be roughly of equal weights. First off the sugar and fat are mixed together. During the mixing process air gets caught on the rough surface of the sugar granules and is sealed in by a film of buttery fat, this forms a light fluffy mixture akin to whipped cream. We use caster sugar in this process rather than granulated sugar because it is finer than granulated sugar and therefore has a greater surface area on which to trap air.
But sugar does more than just trap air within the cake batter. It softens the flour proteins tenderising the mixture, it also lowers the mix’s caramelisation point, allowing the crust to develop a crisp golden consistency at relatively low temperatures. Finally, sugar also helps keep the cake moist and edible for many days. Most of the moisture in a cake comes from the eggs, which provide the mix with the majority of its liquid. When everything is mixed together the eggs produce a foam which surrounds the air bubbles in the mixture protecting them from the heating process and which is also stiffened by starch in the flour. Proteins in the flour join together creating a network of coiled proteins that we know as gluten. Gluten is key to holding the cake together, it expands during baking and then, when cooling, coagulates and is able to support the cake’s weight.
For the bakers out there you may have noticed that we have missed out the baking powder, this may come across as some voodoo magic but it is basically just dried acid and an alkali. Adding water and heat to this mix allows them to react producing CO2.
Now it’s not just getting the right measurement of ingredients, but it’s also essential to get the temperature of the oven precisely right. Too low and the expanding gas cells coagulate producing a coarse heavy texture leading to the cake sinking, too hot and the outside starts setting before the inside even finishes baking, leading to a volcano-looking cake.
So when you next grab a cupcake just take a little time to appreciate the exact science that went into baking that mouth-watering little treat. So many things that could go wrong it’s a miracle we ever found out how to make these soft icing covered delights.
Post by: Jennifer Rasal