Washes

Water is often brushed or sprayed on shaped breads before baking to ensure a crisp crust and to promote the gelatinization of the starch on the surface of the bread. Beaten eggs as a wash create a glossy, shiny crust and seal the moisture in the bread. Typically, whole eggs are used. A wash of only yolks would burn too quickly, especially at the higher temperatures required for baking most breads.

Milk or cream is often used for breads baked at lower temperatures. Because the lactose in milk or cream caramelizes at 170°F/77°C, it gives breads a darker crust than water. In addition, the bread will bake a little faster because the milk fat acts to conduct heat.