Mozzarella gets its signature stretch from a process of kneading and pulling curds in hot water.

The 'pasta filata' method originated in Italy and is essential for producing cheeses like Mozzarella and Provolone. The process begins when the curd reaches a specific pH level, usually between 5.2 and 5.4. At this acidity, the calcium phosphate that holds casein proteins together begins to dissolve, making the structure flexible.Once the curd is immersed in water heated to approximately 140°F to 160°F (60°C to 71°C), the proteins become highly mobile. Mechanical stretching then pulls these casein molecules into long, parallel fibers. This structural alignment is what gives Mozzarella its unique ability to stretch up to several feet when melted on a pizza.Research published in the Journal of Dairy Science highlights that the fat content and moisture levels also play critical roles in this elasticity. If the water is too cold, the proteins will not align. If it is too hot, the proteins denature and the cheese loses its structural integrity. This delicate balance of chemistry and physics has been perfected by Mediterranean cheesemakers over centuries.