Cooking and stirring
The objective of this step is to further develop acidity and to cause the expulsion of whey from the curd. Not all cheeses undergo this step. Refer to the recipe. Gentleness is called for!
For harder cheeses where cooking and stirring is used, the temperature must be increased very slowly, no more than 2°F every 5 to 7 minutes. The curds should be stirred very slowy and gently to prevent the matting of the curds and to aid in the expulsion of whey from the curds. Once the final cooking temperature is achieved, the curds are usually allowed to set for a time and settle to the bottom of the pot creating a clear separation between the curds and whey. Prior to draining of the whey (which should be saved for whey-based cheeses like Ricotta, or to be used in bread, or even to water garden plants), the curd can be tested for proper consistency by placing some in the palm of your hand. If you squeeze them together, they should mat into a mass and be somewhat firm and resilient, however you should also be able to separate them by agitating them with your thumb or finger.