Answer: These are both leavening agents used in baked goods. Baking powder (pictured) contains baking soda, cream of tartar, and cornstarch. It begins to rise when it becomes wet and rises again when it is exposed to heat. That is why you see “double-acting” on the label.
Baking soda is typically used when the recipe contains an acid, such as buttermilk or yogurt. When the soda and the acid are combined, it will begin to rise immediately.
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