The One Ingredient You Shouldn't Substitute In Angel Food Cake

Angel food cake is a famously airy confection with a pillowy crumb that puffs up high as it bakes, creating an ethereal texture that inspired its "food of the angels" name. This classic dessert, often served with fresh berries and whipped cream, gets its fluffy consistency from egg whites beaten with cream of tartar. The acidic ingredient stabilizes the whites, and is so important to creating the cake's melt-in-your-mouth tenderness that you should never use a substitute.

This light and delicate cake is made without any fat — no butter, oil, egg yolks, or milk — and doesn't rely on leavening agents like baking soda or powder. Instead, its lift comes from egg whites whipped to medium peaks with cream of tartar. The proteins in the whites are prevented from binding together by the acid, which stabilizes the small, air-filled bubbles that support the cake. Without cream of tartar, the cake would collapse, so it's best to save this dessert for another day if you don't have it. Substitute acids like lemon juice or vinegar are less powerful and won't fluff up the cake as well.

Make sure your cream of tartar is fresh — don't use a jar that's been sitting in the back of your spice rack for years — and bring the egg whites to room temperature before whipping them. The cake should be baked in tube pan that hasn't been buttered or oiled, allowing the batter to cling to the sides as it rises, which further helps it puff up.

Cream of tartar is made in a surprising way: the powdery ingredient is a byproduct of the winemaking process. Grapes naturally contain tartaric acid, and as they ferment to make wine, tartar crystals form on the insides of barrels. These crystals are scraped off and ground into cream of tartar.

Meringues and macarons (which you can use to make bite-sized ice cream sandwiches) also depend on cream of tartar's ability to stabilize egg whites, typically using a ratio of ⅛ teaspoon of the powder per egg white. It can also stabilize homemade whipped cream (instant pudding mix works for this as well), which would otherwise eventually separate and become loose and watery. Whipping heavy cream with cream of tartar prevents the water from separating from the air bubbles.

Cream of tartar offers other benefits for texture and flavor. It keeps sugar from crystallizing, so using it to bake cookies results in a chewier texture instead of a crispy one. It also provides the tangy flavor commonly associated with snickerdoodles. In a pinch, you can also combine it with baking soda to create baking powder.