Curd is a dairy product obtained by coagulating milk in a process called curdling. Havarti is made like most cheeses, by introducing rennet to milk to cause curdling. This mainly involved salting, curing, curdling, drying, pickling, fermenting, and smoking. Starch is sometimes added to custard to prevent premature curdling. Curdling can be prevented by using lower temperatures and stirring. Added to Hollandaise sauce, mustard can inhibit curdling. In sauces which include milk or yogurt, overheating often causes curdling. It is made by curdling the milk and separating the whey from it and sugar. Higher temperatures will denature the proteins, resulting in slower or even no curdling. He learned to reduce milk without scorching or curdling it. This is simmered on low to medium heat, to prevent the coconut milk from curdling. The whey is then removed during curdling, and the result aged at low temperatures. Do not further cook once egg is added, to avoid curdling. It differs in that more vinegar is used and it is not heated while curdling. Curdling can occur in different cooking processes.