If I put baking soda in a vanilla cake, it will result in a very tall cake, because it creates lots of bubbles when it’s added to liquids, and there are liquids in cake ingredients.

What is a leavening agent?

A leavening agent is an ingredient used in baking that will make the dough expand. It will do this by releasing a gas called carbon dioxide once it’s mixed with liquid or acid or when it’s heated. The more the dough expands, the higher the cake will rise.

Some of the leavening agents used in baking are:

Yeast - Yeast is a microscopic organism. It is used for baking and beer. It is mostly used for bread. Yeast is used in bread to help it rise. Yeast works in different ways depending on if there's oxygen. With oxygen, yeast turns sugars into carbon dioxide and water. This is what happens with bread. Without oxygen, it does something called fermentation. Fermentation is when the yeast turns sugars into carbon dioxide and alcohol. This is what happens with beer. 

Baking Soda - Baking soda or sodium bicarbonate is used for baking, cleaning and deodorizing. Baking soda is free of harsh chemicals and is also a pest remover. It is used in baking as a leavening agent. It is activated when it's mixed with an acid like buttermilk, lemon juice, yoghurt or vinegar. When it’s mixed with acid it forms water, a salt and carbon dioxide. 

Baking Powder - Baking powder is made out of: Sodium bicarbonate which is an alkali, an acid called cream of tartar, and a filler like cornflower or riceflower. It is also used in baking as a leavening agent. In order for baking powder to work, you must add liquid to the baking powder. The liquid will make the acid and the alkali in the baking powder react just like when you add acid to baking soda, and it will also form water, a salt and carbon dioxide.

Materials:

• Simple vanilla cake mix recipe ingredients (Cooking spray, all purpose flour, white sugar, leavening agent, vanilla extract, salt, eggs, milk, vegetable oil)
• Yeast
• Baking powder
• Baking soda
• 4 small cake pans
• Camera/phone
• 4 mixing bowls
• Spatula
• Handheld mixer
• Measuring cup
• Tablespoon
• Masking tape
• 4 different colored markers
• Wooden skewer sticks
• Ruler
• Oven
• Baking scale

Procedure:

Step 1: Lay out the materials

Step 2: Get the simple vanilla cake recipe

Step 3: Preheat the oven to 350 degrees F (175 degrees C)

Step 4: Line up 4 mixing bowls and label them with masking tape and different coloured markers (No agent, Yeast, Baking powder, Baking soda)

Step 5: Add 2 ⅔ cups flour, 1 cup sugar, 1 Tbsp vanilla extract and 2 pinches of salt to each bowl. Add 1 Tbsp of the leavening agent needed (or none) to each bowl. Stir the ingredients in each bowl with a spatula. Add 3 eggs, ¾ cup milk and ¾ cup vegetable oil to each bowl. Beat with an electric mixer on low speed until the batter in each bowl is smooth.

Step 6: Get 4 small cake pans. Weigh each pan on the baking scale. Add 1 cup of each of the 4 cake mixes to a pan and then weigh each pan again. 

Step 7: Start to bake. Line up the cakes in the middle of the oven and make sure to write down the order they are lined up in. Write down the name of each leavening agent with a marker on masking tape and stick each piece of tape on the top of the oven in the order the cakes are lined up. Bake the cakes for 30 minutes.

Step 8: After 30 minutes, take the cakes out of the oven and line them up on top of the oven with their labels. Weigh each cake on the baking scale. Then, poke a wooden skewer stick with the flat side down into the highest part of each cake and mark how high they are with the colored markers. Then measure from the bottom of the wooden skewer stick to the marker dot with a ruler to see how tall the cake is. 

Step 9: Try a piece of your cake. Cut off any parts of the cake that might have gotten marker on it.  

Step 10: Record your qualitative observations in a chart:

• Taste
• Appearance (dark, light)

Step 11: Record your quantitative observations in charts (height and weight of cake)

Table 1. Height of baked vanilla cakes   

Table 2. Weight of raw vanilla cakes    

Table 3. Weight of baked vanilla cakes    

Table 4. Average height and weight of baked vanilla cakes 

Qualitative Observations - Taste and Color of baked vanilla cakes

Qualitative Observations

Trial 1- Sample 1 and Sample 2                 Trial 2- Sample 1 and Sample 2               Trial 3- Sample 1 and Sample 2

Analysis

Based on the data that was collected, it showed that the baking soda and baking powder were almost the same. The average height of all of the trials actually showed that baking powder ended up making the vanilla cakes rise the highest, but only by 0.06 cm. The cakes with yeast (6.03 cm) were higher than the cakes with no leavening agent by 0.56 cm but they were not as high as baking powder (8.77 cm) and baking soda (8.83 cm). 

Baking powder is also recommended instead of baking soda for vanilla cakes, because it made the cakes taste better. The cakes with baking soda tasted a little bit tangy. This was probably because there weren’t enough strong acids in this recipe to make all of the baking soda turn into carbon dioxide, salt and water, which would leave some of the baking soda behind. Baking soda is an alkali, and alkalis usually taste bitter, which is probably why the cake tasted tangy. Baking powder already has an acid in it (cream of tartar), which means it will still work if there aren't any strong acids in the ingredients. There’s also something called the Maillard reaction in cooking and baking that says that more alkali ingredients will make things turn brown faster. The baking soda cakes got a little too dark after half an hour of baking, which meant they were probably more alkaline than the baking powder cakes which were a nicer golden color.

For the weight of both of the raw and the baked vanilla cakes, the baking powder and baking soda cakes weighed pretty similar, and the yeast and no agent cakes were heavier than the baking powder and baking soda cakes. Because the baking soda and baking powder cakes were lighter, it meant that there was more carbon dioxide in the cake batter, which helped the cakes rise higher. The yeast and no agent cakes were heavier, so they produced less carbon dioxide, making their cakes less high. Based on the background research, baking powder should have produced more carbon dioxide than baking soda, because there weren’t really any strong acids like buttermilk, yoghurt, vinegar or lemon juice in this recipe, but the heights and weights for both of the baking soda and baking powder cakes were pretty close, so I thought I’d check to see if any of my ingredients were acidic. I read that vanilla extract can be acidic, so I decided to measure the pH of the vanilla extract that I used, and it was around 4, which is acidic. Maybe that’s what helped the baking soda cake produce more carbon dioxide in this experiment.

Baking powder, baking soda and yeast release carbon dioxide when they’re mixed with the right ingredients. Carbon dioxide makes the cake more light weight or less dense. The baking soda and baking powder cakes must have produced more carbon dioxide than the yeast cakes, and the yeast cakes produced more carbon dioxide than the no agent cakes. The no agent cakes should actually produce no carbon dioxide, since there is no leavening agent in them.

My hypothesis was incorrect. The baking powder actually made the vanilla cakes rise slightly higher than the baking soda did, but it was almost a tie. In this vanilla cake recipe, baking powder seems to have produced the most carbon dioxide, which made the cakes rise the highest. The baking powder cakes also tasted the best and had the nicest looking color after they were baked. Overall, baking powder is the best leavening agent to use in this vanilla cake recipe, because it made the cakes rise the highest and it made them look the best and taste the best!

Applications to the real world are: 

My experiment will help bakers to know which leavening agent makes vanilla cakes rise the highest and look and taste the best. 

Cakes that rise higher are more fluffy or less dense. Fluffier cakes might look more appealing, and with this recipe they would also taste better, so more people would want to buy them! 

Sometimes bakers might want denser cakes for things like stacking cakes for a wedding and adding double layers to cakes. My experiment will also help bakers learn how different leavening agents will affect the density of the cake. Knowing more about how leavening agents work would help them make cakes that are less fluffy or more dense. 

Knowing that more alkali ingredients will make the cake brown faster is also important for bakers to know so that their cakes will turn out the color they want and end up tasting the way they want.

For the cost of the leavening agents in my cake, baking soda was the cheapest, baking powder was in between and yeast was the most expensive. Baking soda was $0.09/tbsp, baking powder was $0.25/tbsp and yeast was $1.66/tbsp. This is something bakers can think about when they are making lots of cakes. Even though the baking powder was $0.16/tbsp more than baking soda, my experiment shows that it would still be the best leavening agent to use for this cake recipe, because the better look and taste makes up for the extra cost.

Next steps 

Some next steps for my project are trying out different leavening agents in different dough, like bread, pizza dough, cookie dough etc. I might also find another cake recipe and try the same experiment on it and see if this recipe might have a different reaction than others. Also, I might try adding buttermilk instead of milk to this vanilla cake recipe to see if a stronger acid will making the baking soda cakes rise higher and taste better. One other thing that I would do is try adding whipped egg whites to a recipe that doesn't have eggs in it to see what it would do to the cake. Whipped egg whites are also a leavening agent.

The pinches of salt - I didn’t count or measure the salt so it’s a source of error. I tried my best to pinch the same amount of salt each time but that may not have always worked.

Measuring cake heights - Measuring the cake heights with the skewer sticks and markers may have been a source of error, because it was hard to put the marker line in the exact spot of the highest part of the cake. I still thought this was the most accurate way to measure the cake heights, because just putting a ruler behind the cakes highest part was hard to tell where the top of the cake lined up. 

Oven temperature - I was worried the temperature may have been different in different spots in the oven, so I put the cakes in different orders in the oven for different trials, but it seemed to not affect the heights of the cakes, so the temperature in the oven must have been exactly the same everywhere.

The yeast - Normally yeast has to be made a special way to work. If I had added the extra warm water to make the yeast work better, then there would have been more than one manipulated variable, because the cake ingredients wouldn’t have been the same anymore. I decided to see if it would have made a difference, so I made an extra two cakes with the 1 tbsp of yeast dissolved in ¼ cup warm water. The heights and weights ended up being about the same, so it didn’t end up being a big source of error. 

Yeast - when I added warm water to the powder

The cakes weighed 246g and 245g and the heights were 6cm and 5.9cm. They were similar to the yeast cakes I didn’t add warm water to. 

Citations 

22 benefits and uses of baking soda Feb 7 2023 https://www.armandhammer.com/en-ca/baking-soda/baking-soda-products/pure-baking-soda/baking-soda-box https://www.healthline.com/nutrition/baking-soda-benefits-uses#household-uses 

All about the egg (n.d) Retrieved from https://eggs.ca/eggs101/all-about-the-egg/

All about whipping egg whites. (n.d.). Retrieved from https:/www.thespruceeats.com/all-about-whipping-egg-whites-132868/

Baking powder| Good Food (n.d) Retrieved from https://www.bbcgoodfood.com/glossary/baking-powder-glossary

Everything you need to know about yeast October 12 2023 https://www.delish.com/kitchen-tools/a31956082/what-is-yeast

Yeast uses and definitions November 14 2024 https://www.britannica.com/science/yeast

The difference between baking soda and baking powder n.d https://www.youtube.com/shorts/vhVSVOqGdaM

Baking soda vs baking powder n.d  https://www.youtube.com/shorts/dIEqPN6S33o

https://www.fao.org/4/x0560e/x0560e08.htm#:~:text=In%20addition%20to%20oxygen%2C%20they,such%20as%20glucose%20and%20fructose.

Baking powder December 7 2024 https://en.wikipedia.org/wiki/Baking_powder#:~:text=When%20combined%20with%20water%2C%20the,CO2%20%2B%20H2O

Wikipedia - Sodium bicarbonate february 18 2025  https://en.wikipedia.org/wiki/Sodium_bicarbonate

What is yeast? n.d https://www.exploreyeast.com/what-is-yeast/is-yeast-aerobic-or-anaerobic/#:~:text=In%20the%20presence%20of%20oxygen,into%20carbon%20dioxide%20and%20alcohol.

The Difference Between Baking Soda and Baking Powder may 21 2014 https://news.ncsu.edu/2014/05/21/baking-soda-powder/#:~:text=Baking%20soda%20has%20only%20one,like%20buttermilk%2C%20yogurt%20or%20vinegar.

A Dash of Science Baking Soda and Baking Powder october 7 2013https://adashofscience.com/2013/10/07/baking-soda-baking-powder/

I FINALLY understand the Maillard reaction https://www.youtube.com/watch?v=5lKzZc_OO7U

I would like to acknowledge my mom for helping me bake my cakes and for all her motivation for geting me to create the best project that I could.