Science Explanations

Experimenting With Eggs

The first task in our investigation was to “play” with the egg in our XXL Sugar Cookie recipe.

The recipe calls for eggs which acts as a binding agent. So for part 1 of this two part investigation of egg we want to change the amount of beaten egg added to the batter and then change which parts of the egg are added. These alterations will contribute to changes in the texture, taste, and color of the cookie. The original recipe calls for 2 tbsp of beaten egg, but what would happen if we were to add 1 tbsp of beaten egg instead? What would happen if we were to add 4 tbsp of beaten egg? Too little or too much egg can make the cookie very soggy or crumbly and dry.

Lastly, if only egg whites or only egg yolks are added, what will happen? Instead of 2 tbsp of beaten egg, we would add 2 tbsp of egg yolk to one batch and then one 2 tbsp of egg whites to another batch. Since egg whites contain a great deal of water and no fat, they tend to have a drying effect on baked goods. Will the cookie without egg yolk end up dry? Also, egg whites don’t contribute to the flavor very much so will we need to add another ingredient or increase the amount of an already added one to make up for that missing flavor? Or will the lack of egg yolks not make a huge difference in the flavor at all? In addition, a whole egg adds structure and strength as well as moisture and tenderness. How will the lack of the egg whites or the egg yolk affect the structure of the sugar cookie? Egg yolks are great emulsifiers, meaning they work to combine liquid and fats into one cohesive mixture. Without this combining agent, will parts of the cookie be clumpier and generally less cohesive than other parts? By altering all of these ingredients, will the sugar cookie end up worse or better?

For a better explaination of what an egg does in a recipe check out My Blossom Recipe or check out this website.

The Experiment


  • Ingredients (flour, butter, etc. everything besides eggs)
  • Baking time (16 minutes for each cookie)
  • Supplies used (same bowl, same spatula, same cookie sheet)

Independent Variable:

  • Amount of egg and part of the egg
    • Double egg (4 tbsp.)
    • 1/2 egg (1 tbsp)
    • Regular (2 tbsp.)
    • Egg white (2 tbsp.)

Dependent Variable:

  • Affect on the egg

The Results

Egg Reaction Chart

The Results Explained

Cookie #1 (No adjustments to the recipe- the control)

This cookie turned out to be exactly how the cookie was described on the website. It was light, but with a perfect crisp on the outer edges and nice and soft in the middle. The taste of the sugar cookie was just right, not too overpowering with sugar.

So, what happened during this baking session? Just the right amount of everything. The cookie had just the right amount of crunch on the outside from the egg white. The egg binds all the ingredients together and made for a well mixed cookie, not getting a string butter flavor at any one point or another ingredient. The cookie spread out at just the right amount due to the even balance of liquid, not solely relying on the egg for this.

Cookie #2 (Double the egg- 4 tbsp.)

This cookie was giant. It barely spread out, instead it went up. There were a ton of air pockets and this cookie resembled a cake more than a cookie.

So, why did this happen? When an egg is the predominate liquid in a recipe it tends to cause the cookie to puff up creating a cake like texture. To resolve this a simple tbsp. of water will cause the cookie to spread out more. From having to add more flour it is proven that there was a liquid overload. I only added enough flour to at least get the cookie on the cookie sheet in a ball because before it wouldn’t make anything close to a ball. Taking this step did not alter the results much because the cookie was still predominately egg. Taste wise the cookie was consistent with the original taste because the cookie balances out the flavors. The only difference was the slight increase in sweetness, but very tolerable.

Possible changes for next time: Something that I would like to change for next time would be to not add the extra flour and to let the cookie spread out as needed or blow up as much as it wanted. This would give a more accurate representation of what will happen with this exact recipe.

Cookie #3 (1/2 the egg- 2 tbsp.)

This cookie had a lot going on. There was no cohesiveness in this cookie. One side was extremely oily while the other side was extremely dry. On top of that this cookie was either really sweet, really bland or tasted normal.

So, what happened here? A lot didn’t happen in this cookie is almost the better question. We know that a cookie needs to be bound together and mixed properly, but despite the appearance of the cookie being bound together in reality it wasn’t in the flavor department. There was enough egg to make sure that the cookie wouldn’t fall apart in the oven but it didn’t have enough yolk to make the ingredients properly combine. The cookie spread out the same about as before, but was more dry because it was missing liquid.

Possible changes for next time: Something that I am interested in changing for next time is the amount of mixing performed. I feel as if maybe the amount of mixing or lack there of could have contributed to the inconsistent flavors throughout the cookie.

Cookie #4 (Egg whites only)

This cookie was very fragile. The cookie was rough around the edges (literally) and very wet.

So, what happened here? The reaction that happened here slightly mirrored research, but there wasn’t enough egg white to prove these hypothesis. One thing that did hold true was the cookie not being bound together, structurally or flavor. The cookie allowed you to taste each individual ingredient; you got flaks of the flour and then sudden butter overload making the cookie seem uncooked. The cookie was supposed to be sweeter, which is what we got but it didn’t have a consistently sweet flavor.

Possible changes for next time: Something I am intrigued to see if it affects the cookie is if the amount of egg white is doubled or if i wait unil it is fully airated. This I believe will account for the dryness and give the anticipated results.


To check out our experiment with baking soda, click here

Pictures are all original by author
Featured image citation: GraphicsRF. (2019, May 12). Egg with happy face. Retrieved from

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