What You Need to Know
When the pH of milk falls below about 4.6, casein micelles aggregate into curds while whey proteins remain in solution. Lemon juice (pH≈2) or vinegar (pH≈2.5) provides the acid, and mild heating (80–90 °C) accelerates the reaction by increasing enzyme activity and reducing whey viscosity. The process can be precisely timed to achieve the desired curd firmness and texture.
The Science
Primary Reaction
Acid‑induced coagulation of casein micelles