Advanced cheesemakers know that the acidity of milk, cheese whey, and other dairy products can be important to cheesemaking. This acidity testing kit lets you know when to add rennet and when to put curd in the cheese mold. Kit includes 1 testing cup, a plastic syringe, one 1/2 fluid oz. phenolphythalein (color solution), 4 oz. sodium hydroxide, instructions.