Calcium chloride is an additive used in cheesemaking used with store-bought milk and goats milk to create a firmer setting curd for easier cutting when making of hard cheeses. The heat-treating process most commercial milk goes through decreases the amount of calcium leading to a less firm curd. The natural homogenization of goat milk also leads to a less firm curd.
Calcium chloride is often needed when the milk used for cheesemaking has been pasteurized and/or homogenized. During processing, the chemical structure of milk is changed, sometimes drastically. Those changes include a slight decrease in calcium levels within the milk. Calcium is necessary for proper curd formation. By adding calcium chloride to the milk before adding the coagulant, calcium levels are restored.
Calcium chloride is commonly used in making some goat cheeses, which can have a less firm curd due to goat milk's natural homogenization.