Liquids

The addition of milk, water, or another liquid to beaten eggs dilutes and separates the protein molecules, making it more difficult for the molecules to combine. This in turn raises the coagulation temperature and slows down thickening. The addition of milk, for example, allows a stirred custard to be heated to 71°C (160°F) before curdling, because the sugar in the milk dilutes the egg proteins.

The rate at which a liquid conducts heat also affects cooking time: Homogenized whole milk, for instance, conducts heat more slowly than skim milk.