Cheese is quite possibly the noblest endpoint for milk—exalted examples are often put in the same class as high quality caviar or truffles by culinary cognoscenti. Whatever the variety, all cheese goes through the same process. Typically, milk for cheese comes from cows, buffalo, goats or sheep. The first step is to curdle the milk, separating the curds (solids) and whey (liquids). This is accomplished by mixing in a precise ratio of two substances: Bacterial cultures, which acidify the milk, and rennet, a protein taken from calf stomachs. As a rule, softer less aged cheeses get more cultures than rennet, and harder longer-aged cheeses, just the opposite. The next task is to separate as much whey from the curd as possible, using such techniques as cutting, stacking and kneading, depending on the cheese. Then salt is added. Next, the cheese is pressed into a solid shape and left to age for as little as a few weeks to as long as a few years. This final step allows the development of flavor as the bacteria and other ingredients change the cheese’s chemical structure.