In pastry making, why is it important for crème anglaise not to be overcooked?

In pastry making, controlling the cooking process of crème anglaise is crucial because overcooking can cause the mixture to curdle. Crème anglaise is an emulsion of egg yolks, sugar, and milk or cream, which relies on gentle heat to thicken without forming lumps. When heated too much, the proteins in the egg yolks denature and coagulate, leading to a grainy texture instead of the smooth and creamy consistency desired.

The delicate balance of temperature is important; ideally, crème anglaise should be cooked slowly over low heat until it reaches the desired thickness, which is achieved when it coats the back of a spoon. If overcooked, not only does it compromise the texture, but it may also impact the overall quality of the dish, as a separated emulsion affects appearance and mouthfeel. Maintaining the correct temperature is key to achieving the perfect crème anglaise.