MSU Extension

This is the next article in a series by Michigan State University Extension about science activities that children can participate in. This can be done within a family, in a day care setting, as part of school activities, a 4-H club or with any group working with young children.

I love chocolate chip cookies and the many ways they can be made. They can be thick or thin, chewy or crispy, or sparing or loaded with chocolate chips. Is it just luck whether or not they turn out a certain way? Does the right recipe guarantee results? Play with your food and use some science to see what variations can be created with the kids in your life. See if they like what you like.

Here is a basic chocolate chip cookie recipe:

1 cup softened butter (2 sticks)
1 1/2 cups sugar
1 teaspoon vanilla
2 eggs
1 teaspoon baking soda
1 teaspoon salt
2 1/2 cups flour
2 cups chocolate chips (a 12 ounce bag)

1. Cream butter and sugar together. Add eggs and vanilla and mix. Gradually add in the other ingredients in the order listed.
2. Put the dough on a pan in large tablespoons. Bake at 350 F for 15 minutes.

Make this “original” recipe first, then change things up, predict what will happen and eat the results.

Variations: Where the science begins!

Science is not always about knowing the answers. Science is about observing, making guesses, experimenting, getting results and learning from them. You can do that while cooking or in a laboratory.

Fat: Most chocolate chip cookie recipes use softened butter. Why do recipes call for butter in this way rather than oil or melted butter? Predict what will happen if you use a different fat. Different fats melt at different temperatures; might that have an effect? Would a cookie made with melted butter be thicker or thinner? Butter has some water in it, while oil and shortening are pure fat. How might that change the cookie? Some recipes suggest switching all or some of the fat with applesauce, pureed pumpkin or cooked mashed beans.

Flour: There are a huge range of flours available in most supermarkets today. All purpose is the typical flour for chocolate chip cookies, but what do you think will happen if you change it? Different flours have different protein contents, which changes the chewiness of the cookie. Flours also absorb different levels of moisture.

Sweetener: Just as with flours, there is a large range of sweeteners available at the market. Different sweeteners absorb moisture differently. Brown sugar or liquid sweeteners tend to make for a moister cookie. You can also adjust of the level of sugar in your cookie. Is it possible to make an edible cookie without any added sugar? Some artificial sweeteners do not measure the same as traditional sweeteners.

Mixing: Most cookie recipes have you cream the butter and sugar together. Mixing these ingredients will make tiny bubbles that the leavening agent can expand. What do you think will happen if you change the order of mixing?

Leavening: Leaving is what makes baked goods rise. Some baked goods, like popovers, rise when the water in the dough turns to steam and expands. Could the cookie be baked with only steam to make it rise? Baking powder and baking soda both use a chemical reaction (like mixing baking soda and vinegar) to create bubbles and raise the dough. Baking soda needs an acid mixed with it to work, whereas baking powder already has the acid mixed in. Try using both and see what happens. Can chocolate chip cookies be made with yeast? Yeast are tiny creatures that “eat” flour or sugar and release carbon dioxide which makes bubbles appear in the dough. If you use yeast in your dough, the yeast need some time to raise the dough. You can experiment with different times.

Temperature: Some recipes recommend chilling the dough before baking. What would that do to the fat in the dough? How might that change the final product? Would it matter if you bake the cookies at a lower temperature for a longer time?

Pan: Some recipes recommend greasing the pan before baking. Some call for parchment paper. Is this just for cleanup, or does it change how the cookies will bake? Experiment and find out. Does using a flat pan versus one with higher sides change the cookie? Why might things be different?

Hopefully you take some time and use the science of observing, making guesses and experimenting to learn about chemistry, thermodynamics and food science.