Cream of Tartar

Many sponge cake recipes call for cream of tartar whenever egg whites are whipped. Cream of tartar makes the whites smooth and stable for easy folding into the batter without causing the egg-white foam to deflate too much. However, when folding an egg-white foam into a mixture, I find whipping a small portion of sugar into the whites works just as well as cream of tartar. Substituting a small portion of the recipe’s sugar for the cream of tartar is not only just as effective in stabilizing the whites and making them smooth but also simplifies the process since the sugar is already in the recipe. The addition of cream of tartar or a small amount of sugar softens an egg-white foam so that it requires more whipping time to reach the proper consistency. Adding cream of tartar to egg-white foams can also stabilize the millions of tiny air bubbles, thus preventing their collapse in the oven during the cake’s baking and giving the structure the time it needs to set its shape. In some of my sponge cake recipes, such as Classic American Spongecake, cream of tartar is indispensable.