Distinguish between single-acting versus double-acting baking powder.

Although both are chemical sources of carbon dioxide, the one available on the market today is the double-acting baking powder. The single-acting baking powder would be a homemade tartrate form made by mixing baking soda and cream of tartar together. The term single-acting means that it releases carbon dioxide when first moistened, usually within the first two minutes. On the other hand, double-acting baking powders contain baking soda, plus two acids, monocalcium phosphate monohydrate which is fast acting, and sodium aluminum sulfate which reacts with heat in the oven.

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