Baking Experiment! Rolled Sugar Cookies with Varying Flours

Rolled sugar cookies with different flours: cake (pink), all-purpose (blue), and whole wheat pastry (green).

I'm a bit of a nerd, and part of what fascinates me about baking is the chemistry.  Bread goes into the oven elastic-y, sticky, and unpleasantly chewy, and comes out soft, pocketed with air holes, and delicious.  Despite a year of chemistry in high school, and another year in college, I can't explain why this happens.

Magic?

This can be a real problem for me when I try to create my own recipes since I often don't know what will happen when I change a recipe.  For all I know, adding some small ingredient could make my cake collapse or completely ruin the texture of my cookies.  When I wanted to make my Black & White Sesame Cupcakes, I had to scour the Internet looking for a sesame cupcake recipe since I wasn't convinced that adding a bit of tahini to a vanilla cupcake wouldn't destroy it somehow.

Rolled sugar cookies with varying flours.  (Top to bottom) all-purpose, whole wheat pastry, cake.

In an effort to educate myself on baking chemistry, I put How Baking Works by Paula I. Figoni on my Christmas list.  Since then, I've been slowly working my way through it, and am becoming increasingly enchanted by all the science-y stuff going on in my kitchen.  At the end of each chapter, there are experiments you can do so that you can see the chapter's lesson in the real world (just like in chemistry class!).  I recently finished the chapter on wheat flours, and decided to do the book's experiment with different flours in rolled sugar cookies!

(Left to right) cake, all-purpose, and whole wheat pastry flours.

I didn't really want to buy a bunch of flours that I would never use again (seemed expensive and wasteful), so I wasn't able to follow the book's experiment exactly.  I already had cake and all-purpose flour, and I decided to also buy pastry flour.  Unfortunately, the only pastry flour I could find was whole wheat pastry flour.  I decided to go with it anyway.

Sugar cookie dough, labeled and ready for rolling!

After baking, I recorded the diameter of each cookie.  As expected, the cake flour and all-purpose flour resulted in smaller, thicker cookies.  The whole wheat pastry flour caused to cookies to spread more while baking.  According to Paula Figoni, this is because both pastry flour and whole wheat flour are not very good at absorbing water, unlike cake flour.

Average Diameters for Rolled Sugar Cookies

Flour	Average Diameter (inches)
Cake	3.375
All-Purpose	3.406
Whole Wheat Pastry	3.5

Diameters of rolled sugar cookies with varying flours.

After I did all the baking and measuring, I decided to make the cookies pretty!  I followed BrownEyedBaker's excellent tutorial on how to decorate with royal icing.  The cookies turned out very pretty, and color-coded by flour type.  However, I'm not loving the taste of royal icing.  Anyone have suggestions on how to make these taste better?

Rolled sugar cookies with different flours: cake (pink), all-purpose (blue), and whole wheat pastry (green).

Rolled Sugar Cookies

Adapted from Jill's recipe at AllRecipes.

Ingredients
1 1/4 cups (156 g) flour
1/2 teaspoons baking powder
1/2 teaspoon salt
6 tbsp butter, softened
1/2 cups white sugar
1 egg
1/2 teaspoon vanilla extract

Method

1. Mix flour, baking powder, and salt in a medium bowl.  Set aside.  In a large bowl, cream together butter and sugar until smooth. Beat in eggs and vanilla. Stir in the dry ingredients. Cover, and chill dough for at least one hour (or overnight).
2. Preheat oven to 400 degrees F. Line cookie sheets with parchment paper.  Roll out dough on floured surface 1/4 to 1/2 inch thick. Cut into shapes with a round cookie cutter. Place cookies 1 inch apart on lined cookie sheets.
3. Bake 6 to 8 minutes in preheated oven. Cool completely.

Rolled sugar cookies with different flours: cake (pink), all-purpose (blue), and whole wheat pastry (green).