So, this is not the first nor will it be the last time that someone points out my geekiness. But, the reason that the McGee book appealed to me was the back story on the food that we take for granted. Milk is certainly one of those foods. On the surface, it appears to be so simple, but thousands of years of experimentation and cultivation have revealed its sometimes crazy seeming properties. We’re about half way through the section on milk and finishing up the part of the chapter that will give us an understanding of the how and why individual dairy products come together. We decided that there is no more delicious and versatile way to experience the chemistry of milk than to make butter.
First off, milk fat is present in bunches that come together to form a membrane along with some proteins. It is this fat that accounts for most of the calories and the nutrients, in the form of fat soluble vitamins, in milk. It also accounts for the wondrous ability for milk to give us butter.
Butter is a matrix of milk fat. The complex of free and crystallized fat molecules makes butter hard in the fridge and soft on the table. To get to this point though, we need to find a way of breaking the membrane enclosed globules that are found in cream. Since I don’t have any upper body strength to speak of, or any desire to be a charming milkmaid of yore, we used a lovely 21st century tutorial from Joy the Baker. Amazingly easy.
Inside those lovely little fat globules, the fatty acids are found in the two forms I mentioned above: free and crystallized. The formation of these crystals is influenced by the heating and cooling process that the cream is subjected to during pasteurization and the aging of the cream. In theory, this should mean that raw cream butter tastes different from pasteurized cream butter, but I don’t have any first hand knowledge of this myself. Our KitchenAid, with the whisk attachment, went to work agitating the cream to break apart the globules into free floating fat molecules that can come together to form the butter solid. The liquid which is mostly water and casein (milk proteins) is, appropriately, buttermilk. Don’t be dumb, like we were, and throw out the buttermilk. It is delicious.
The butter was a gorgeous yellow color. The color of butter is the result of the carotene content of the fat (see fat-soluble vitamins above). High carotene content is a surefire indication of the diet of the cow and hopefully means that the cows were the other sort of pasturized.