Throughout the quarantine period, you may have taken up baking as a hobby to keep you busy. Whether it be cookies, cakes, or bread, baking is a fun, delicious activity for everyone. But have you ever wondered how baking can relate to chemistry? In fact, several chemical reactions and chemistry related interactions occur between ingredients during the baking process. Keep on reading to learn about some of these chemistry concepts associated with the formation of cake!
Acids and Bases
Acids and bases are part of the pH scale, which ranges from 1-14. Anything below 7 is acidic, anything above 7 is basic, and 7 is neutral. All of the ingredients required to make a cake are either an acid or base. Assume that baking soda, honey, and almond milk are part of the recipe. Baking soda has a pH of 9 (base), honey has a pH of 3.9 (acid), and almond milk has a pH of 6 (acid). Baking soda (base) reacts with honey and almond milk (both acids), neutralizing the mixture, creating carbon dioxide gas, water, and salt. As a result, the cake traps the gas and rises. This is what gives cakes a fluffy, soft texture.
Endothermic Process
An endothermic reaction is where a system, in this case, the cake batter, takes in heat from its surroundings, the oven. This means that the heat is transferred from the oven to the cake. The cake pan may continue to retain this heat energy even after it is removed from the oven. As a result, the cake continues cooking for around an hour before it cools down.
Gas Laws
Gas laws demonstrate the relationships between volume, pressure, and temperature. While there are many formulas for these laws, one, in particular, that relates to baking is:
V ∝ T (P constant), also known as Charles' Law
In this situation, the volume of the cake is proportionate to the temperature when pressure remains constant. In gas laws, temperature is always measured in the Kelvin scale.
So let’s start out by converting our temperatures to Kelvin (K):
Prior to being placed in the oven, the batter is left out in room temperature, which is:
68°F = 293 K
The oven temperature is set to:
325°F=436K
When you divide 436K by 293K, you get approximately 1.5. Knowing that volume and temperature are proportionate, the cake would come out of the oven with 50% more volume.
I hope you learned about how chemistry concepts can be applied to cakes. Happy baking!
Written by: Ashlee Liu
References:
Yan, Weichen. “Knowing the PH Levels of Your Favorite Beverages Is the Smart Way to Drink.”Spoon University, 2019, gdpr.spoonuniversity.com/#:%7E:text=Milk’s%20pH%20level%20ranges%20from,pH%20levels%20of%20around%206.
Markings, Samuel. “What Is the PH Level of Baking Soda?”Sciencing, 26 Apr. 2018, sciencing.com/ph-level-baking-soda-5266423.html.
“How Acidic Is Honey?”HoneyBeeSuite, 2016, www.honeybeesuite.com/how-acid-is-honey.
Elert, Glenn. “Gas Laws –.”The Physics Hypertextbook, physics.info/gas-laws. Accessed 18 June 2020.