Baking powder is a leavening agent used in baking to help baked goods rise. Aluminum-free baking powder is a type of baking powder that does not contain aluminum compounds. Instead, it uses other acidic compounds to react with baking soda and produce carbon dioxide gas bubbles, which leaven the batter or dough. Here are some key points about aluminum-free baking powder:

• Faster acting: Aluminum-free baking powders react with liquid and not with heat, which makes them faster acting than most double-acting powders.

• Risk of chemical reaction: There is a risk involved with aluminum-free powders that the chemical reaction will have petered out if you take too long between mixing the batter or dough and putting it in the oven. This risk is small, and it is only a risk for very slow bakers.

• Taste: Aluminum-free baking powder does not have a metallic aftertaste that can linger in baked goods, unlike baking powder containing aluminum.

• Rising: Because aluminum-free baking powder does not work as well in heat, you dont get as much "oven spring," which is the technical term for cakes and breads rising in the heat. Therefore, you should put the batter or dough into the oven fairly quickly.

• Homemade: You can make homemade baking powder by combining twice the amount of cream of tartar, which is the acidic part, with half the amount of baking soda.

Overall, aluminum-free baking powder is a good alternative to baking powder containing aluminum, especially for those who are sensitive to the metallic aftertaste. It is important to note that aluminum-free baking powder may require faster baking times, so it is important to follow the recipe instructions carefully.