Is making cheese a physical or chemical change?

* Chemical Reactions: Cheese making involves several chemical reactions:

* Coagulation: Milk proteins (casein) are separated from the whey by adding rennet or acid. This is a chemical reaction that changes the structure of the proteins.

* Acidification: Lactic acid bacteria ferment lactose (milk sugar), producing lactic acid. This acidification further alters the proteins and influences the texture and flavor.

* Enzymes: Rennet, a natural enzyme, breaks down milk proteins into smaller pieces, contributing to the unique texture of cheese.

* New Substances Formed: The original components of milk (lactose, casein, fats) are transformed into new compounds during cheesemaking. The resulting cheese has different properties than the original milk, including texture, taste, and smell.

* Irreversible: Once milk is transformed into cheese, it can't be easily reversed back to its original state.

While there are physical processes involved (like cutting, pressing, and aging), the core of cheesemaking is based on chemical transformations.