Since the simplistic, breadlike, honey-sweetened “cakes” of Ancient Egyptian
civilizations, humanity’s knowledge of cake-making has evolved into the decadent, frosting-smothered desserts seen in bakeries today. However, in order to truly understand how chocolatey sweets come to life, they must be examined at a chemical level. Only then, would it be possible to create a scientifically perfect chocolate cake.
Before an exploration of how to make the perfect chocolate cake may be approached, the definition of the ‘perfect chocolate cake’ must be determined. While this phrase likely means something different to every individual, some characteristics that are widely agreed upon include a fluffy, light texture; a deep, chocolate flavour; a moist crumb that melts in your mouth; and a
silky, creamy frosting to top it all off.
To achieve the first quality, a pillowy texture, multiple factors come into play. Different ingredients are favourable for this outcome depending on the storage of the cake. Oil is the preferred fat in this case, as it is much less dense than butter, which helps the rise of the cake and allows for it to be light. Leaveners are also largely responsible for texture, as sodium bicarbonate in the form of baking powder is essential for the tiny pockets created within the cake. Baking
powder is a complete leavener, meaning that it already contains both an acid and a base, and thus requires only H2O to be activated. The chemical reaction causes carbon dioxide bubbles in the batter, which allow the cake to increase in volume and expand. The type of flour used is also a crucial element to consider; cake flour, which is the preferred type for cake batters, has a protein
content of 5-8%, which results in a softer cake than the 10-13% protein content in all-purpose flour.
Flavour is obviously another essential part of a quality dessert. The flavour compounds of cake coat the taste buds, which allow the eater to experience the taste. When making chocolate cake, bakers often prefer Dutch-processed cocoa, which is cocoa powder that has been alkalized by soaking in a potassium carbonate bath. In this process, the pH of the cocoa powder is increased from about 5.5 in its natural state, to 7 after the alkalization. Dutch-processed cocoa
powder is preferred in traditional chocolate cakes because the more alkaline state of the cocoa powder prevents an imbalance in the acidity that is already neutral, thanks to the neutral leavening power of baking powder. Aside from the chocolate taste itself, there are additional flavourings that are said to enhance this main profile, including vanilla, citrus, and coffee. Fragrance and flavour perception stems from the olfactory bulb at the back of the nasal passage. There are five key flavours that your taste buds can identify: sweet, salty, sour, bitter, and savoury. Usually, these flavours are featured in tandem with each other, like in sour gummies, which are made with sugar for a sweet taste and citric acid for tartness. Featuring an additional flavour in chocolate cake contrasts the very strong, overpowering profile of chocolate; for example, coffee is often used as a ‘secret ingredient’ in chocolate cake, because the bitterness of the coffee offsets the sweet decadence of the chocolate.
A moist, melt-in-your mouth structure is another oft-desired feature in cakes. This element ultimately comes down to the ‘wet’ ingredients used in the batter and the incorporation of the ‘wet’ and ‘dry’ ingredients. If the cake is meant to be stored in the refrigerator or for multiple days, oil is preferable over butter because it has a lower freezing point. It does not solidify when cooled, which would otherwise result in a dry, crumbly cake. When incorporating the wet and dry ingredients, it is crucial to prevent overmixing the batter. Overmixed batter
reduces the air pockets in your batter, which interferes with the structure and deflates the final product. In cakes made with wheat flour, mixing causes gluten strands to form, which is excellent for bread, but not so much for cakes, as too many gluten formations result in a tough dessert. For optimal results, bakers tend to stop mixing immediately once there are little to no dry spots of flour left.
There are hundreds of types of frostings, all made with different methods and of varying difficulties, but one popular one is Swiss-meringue buttercream, which pairs excellently with cakes. Many prefer this frosting because of its airy texture, less-intense sweetness (it does not completely rely on sugar for structure, so it requires less of it), and distinctly buttery taste. Swiss-meringue buttercream is made using egg whites, granulated sugar, and butter, along with
any flavour additives. Using a double-boiler method, the egg whites and sugar are mixed, then heated, allowing for the solid sugar particles to dissolve into the liquid egg whites, which creates a viscous, homogenous mixture. The heat applied to the mixture causes the particles to move faster and spread farther, allowing the two substances to incorporate evenly. This heating also aids the next step, which is whipping the mixture into a meringue; the heat causes the egg proteins to unravel and become easier to whip, as well as melts the sugar into a syrup that stabilizes the air pockets in the meringue. Once your meringue is whipped, butter is added, creating an emulsion in which the egg whites and fat in the butter are being forcibly combined. In the process of becoming a smooth emulsion, the ingredients resist and go through stages of
looking curdled, soupy, and separated, before finally reaching a state of creamy frosting.
At its core, baking is simply chemical reactions and a harmony of flavour compounds. To recognize this and use the precise chemistry behind desserts to improve them guarantees the best tasting sweets possible. Approaching baking with a scientific mindset by always being ready to experiment, make observations, and test out new theories, ensures a lasting success in an individual’s desserts and curiosity surrounding the science behind food.