Bold text

To transform milk into a solid form, it must be concentrated (curdled). This process takes place after appropriate acidification through the addition of acid cultures and rennet or rennet substitutes, as well as bringing the milk to renneting temperature (about 30 to 34 °C). The protein in milk consists of 80 percent casein and 20 percent whey proteins (albumins and globulins). During coagulation, the casein is broken down and a three-dimensional network is formed via calcium bridges. Contraction of this network expels the whey proteins, and the entire process typically takes 10 minutes to 2 hours, depending on the cheese style. Coagulation occurs under the action of lactic acid bacteria and enzymes, and—with a few exceptions such as sour milk cheeses and certain fresh cheeses—through the addition of rennet or rennet substitutes.