Why is it recommended that a copper bowl be used when whipping egg whites?

There is no scientific evidence to suggest that a copper bowl should be used when whipping egg whites. While copper bowls are often used in classical pastry-making, this is primarily because they are good heat conductors, which can be helpful when making certain desserts. However, for the purpose of whipping egg whites for meringues, chiffon cakes, or other recipes, a copper bowl provides no particular advantage. A clean glass or stainless steel bowl is equally effective and more commonly recommended.