Savory or sweet batters prepared from flour and liquids serve a similar purpose as bread crumb coatings. They enhance flavor, seal in moisture, and provide a crunchy texture to foods. Batters can be thin and light like Japanese tempura, or they can be thicker like a buttermilk or beer batter. Many different starches and liquids can be used for batters. Leavening agents including eggs, whipped egg whites, baking powder, or yeast are sometimes added to lighten the batter.