Cheesemaking equipment and methods vary from cheesemaker to cheesemaker, but the basic principles involved have remained unchanged for thousands of years.
In a typical cheese-making operation, the first step is preparing the milk. Although smaller factories purchase unpasteurized milk that already has the bacteria present to produce lactic acid (necessary for curdling), larger factories purchase pasteurized milk and must add bacteria culture to produce the lactic acid. (Look at the Fig 1.)
Next, the curds must be separated from the whey. Animal or vegetable rennet is added, and then the curds are agitated and cut using large knives. As the whey separates, it is drained. The curds are then pressed into molds, if necessary, to facilitate further moisture drainage, and aged for the proper amount of time. Some cheeses are aged for a month, others for several years.
The milk ideally
Milk is pumped straight from the milking parlor to the dairy where it is checked and tested to ensure it is pure and clean. it may then be pasteurized, typically at 165ºF (73ºC) for 15 seconds. The milk is transferred to a vat and heated until it reaches the acidity level required for the type of cheese being made.
Once the acidity reaches the desired level, a special cocktail of lactic bacteria or starter culture is added. This both converts the lactose to lactic acid and contributes to the flavor, aroma, and texture of the cheese. (Too much or not enough acidity results in imperfect cheeses.) Most cheeses are made by adding rennet (derived from the stomach of a milk-fed animal) or another coagulant to make sure the protein and fat in the milk bond and are not lost in the whey. Curdling is the fundamental step in cheesemaking, as the degree of coagulation determines the final moisture content of the cheese, and this in turn affects the speed of the fermentation process.
Separation of curds and whey
The freshly formed curd looks like white jelly, while the whey is a yellow-green color. Gently separating the curds from the whey creates soft, high-moisture cheeses, while cutting the curds expels more whey and produces harder cheeses. The finer the curd is cut, the harder and finer-grained the final cheese. The whey is drained off once it reaches the desired acidity.
Shaping and salting
The curds are then piled into molds or hoops and may be pressed before being turned out of their molds. Once out of the mold, the cheese is rubbed or sprinkled with salt or soaked in brine before being placed in a cold room or cellar to age.
The aging process is the art and science of cheesemaking, as it brings out the character of the milk and the unique flavors attributed to the grazing. A good affineur, someone who ripens cheeses, can nurture the simplest cheese to yield up every nuance of flavor. Artisan cheeses vary from day to day, depending on the grazing, the season, the conditions in the cheese room, and the cheesemaker; so, unlike wine, cheese has a vintage every day, which is what makes it so extraordinary and wonderful.