That's very interesting! Does this apply to cakes as well or just cookies?
Yes Becky, it applies to cakes as well. In fact it’s probably more critical in chemically leavened cake than in cookies.
When butter is too warm it will never aerate properly. Soft butter simply cannot hold the air pockets. Most bakers think of creaming butter as a method of mixing ingredients. But creaming butter enables leavening. Creaming is often referred to as mechanical leavening, but that’s not quite accurate.
In a chemically leavened cake, a good and uniform rise depends on the CO2 expansion. The aerated butter doesn’t create the rise. Rather, aerated butter creates the air pockets to trap the CO2. The flour’s gluten network creates the framework around the air pockets, allowing for increased volume of the mass. The interplay between creamed butter, chemical leavening, and flour is the reason why it’s important to thoroughly sift the chemical leavening throughout the flour.
My interest in baking started in 2001 when I purchased Nancy Baggett’s The All-American Cookie Book. I was so enthralled I baked nearly every cookie in her book. Almost immediately I noticed “room temperature” butter seemed problematic. I found the creamed butter was often too soft to hold aeration. While the cookies tasted great, I was convinced the distinctively amateurish look was somehow related to the creaming. So instinctively I started using cold butter. I also started converting all of the recipes from volume to metric measurement. Suddenly my cookies not only tasted great, but they looked amazing.
Yet in the back of my mind I thought I was wrong to use cold butter. So I researched cold butter creaming. What I learned confirmed the use of cold butter is the correct method.
A baker named Sarah Phillips has a site called Baking911.com. It’s now called Craftybaking.com. At the time, Phillips was the only source I found on cold butter creaming. That lone article reassured me that I was going about it correctly.
As I took more baking classes in different culinary programs, I found most culinary programs also creamed with cold butter. So Phillips was not alone in advocating for the use of cold butter.
Although I recommend using butter at 65°F (18°C), the truth is I take the butter straight from the fridge and toss it into my mixer bowl. I’m neurotic about temperature ingredients. I find straight out of the refrigerator gives me a finished dough temperature below 70°F (21°C).
The finished dough temperature is very important to the texture of finished product. Friction creates an extraordinary amount of heat. I always say that temperature is an ingredient. Baking is chemical reaction; heat is a major factor in triggering chemical reaction. Therefore, controlling amount of heat we put in the mixing bowl is just as important to the outcome as the amounts of the other ingredients.
When Sarah Phillips created her new site craftybaking.com, she keep most of the original content of Baking911.com. Her site is an excellent source on baking methods.
Phillips’ original article on creaming butter.
https://www.craftybaking.com/howto/mixing-method-creaming
Phillips index of how to blogs.
https://www.craftybaking.com/howto
Phillips baking glossary
https://www.craftybaking.com/glossary
These photos are from a batch of chocolate chip cookies I baked.
Temperature of the butter I used: 48.7°F (9.27°C)
Temperature of the dough after mixing: 67.6°F (19.77°C). I also used a cold egg out of the refrigerator. Even with cold butter and eggs, friction heat increased the final dough temperature nearly 20°. If room temperature butter is alrrady too soft to properly aerate. Once the dough is finished, that butter will be on the verge of collapse before it even hits the oven heat.
