The Chemistry of Cookies: Why the heck did that happen?

To understand the fundamentals of cookie baking, let’s talk about the basics. Most cookies begin with creaming butter and sugar together. How many times have we done this and had NO idea why it was really necessary? Yes, everything has to come together but is there more going on here than putting a batter together? In fact, there is.

The sharp crystals of the sugar dig and cut into the butter creating air pockets which will help make your cookies light and fluffy. If you are doing this by hand, it is going to take at least five minutes to achieve. It is the workout portion of cookie-making. I like to start the creaming process from one spot and make my way around the bowl by turning it in a counter-clockwise direction. It helps to use very room temperature butter but you don’t want it to be too soft because then it will just melt into the sugar and you will not create the air pockets that poof up your cookies to be light and fluffy.

The rest of the process depends a lot on what kind of texture this cookie is going to have. For a chewy cookie, there will need to be high moisture content. For crisp texture, the dough will be low in moisture. For soft cake-like texture there will be a lot of liquid and less sugar and fat.

TROUBLESHOOTING

My cookies spread out and are as flat as pancakes!

Sadly this recently happened to our dear friend Tori as she participated in our cookie challenge! According to The Professional Pastry Chef, the best book on baking I have ever come across and HIGHLY recommend, the spreading out of cookies can be the result of high sugar content when combined with overmixing. “The higher the sugar content, the more the cookies will spread.” They suggest replacing the sugar you used with icing sugar instead to reduce this tendency. Sometimes this can also happen because the butter is too warm and will lose its structure so put it in the fridge for a while to cool down.

My cookies are as hard as rocks!

According to The Prepared Pantry’s Cookie Troubleshooting Guide, the oven may have been set too low so bake at a higher temperature for a shorter period of time. They also suggest you use brown sugar if the recipe called for regular white sugar. Make sure you are not adding too much flour, this is where disciplined measuring comes into play. Too much flour can result in a tough cookie. When you add the dry ingredients to the wet you do not want to overmix the dough. You want to mix it until just incorporated. Overmixing can get the glutens working too hard and you will turn out a tough cookie!

My cookies always burn on the bottom!

The Professional Pastry Chef writes that because of the high sugar content of cookies, they are susceptible to overbrowning and suggest double-panning the batch to prevent them from browning too much on the bottom before they fully bake on the top. They also recommend baking at 375F (unless they are macaroons which require more heat) so if your recipe calls for a higher temperature than 375F, you are baking them at too high a temperature.

I hope that helps answer some of your questions about baking cookies. If you have had an issue that I did not address, please let me know and I will see what I can find.

I hope we all have fun baking cookies together no matter what the results! I love baking because it is where chemistry is mixed with magic and a lot of love. You never know what is going to happen.