Why does a cake not rise when baking powder is added?

There are a few reasons why a cake might not rise even after adding baking powder:

1. The baking powder is old or expired: Baking powder loses its effectiveness over time. Check the expiration date and replace it if needed.

2. The baking powder wasn't properly measured: Baking powder is very potent, and even a small error in measurement can affect the cake's rise. Use a measuring spoon and level it off with a straight edge.

3. The recipe was not followed correctly: Some recipes call for specific amounts of liquid, fat, and sugar, all of which play a role in leavening. Make sure you followed all the recipe instructions.

4. The oven temperature is too low: Baking powder works by releasing carbon dioxide gas, which expands and creates air pockets in the batter. If the oven temperature is too low, the gas won't expand enough to create a rise.

5. The batter was overmixed: Overmixing develops gluten in the flour, which makes the cake tough and dense. Mix only until just combined.

6. The ingredients were too cold: Cold ingredients can hinder the baking powder's ability to activate properly. Make sure all ingredients are at room temperature before mixing.

7. The cake was baked for too long: Baking a cake for too long can dry it out and cause it to collapse. Check the cake for doneness using a toothpick or cake tester.

8. The cake pan was not properly greased and floured: This can cause the cake to stick to the sides and prevent it from rising evenly.

9. The recipe itself is faulty: Sometimes, recipes simply don't work as intended. It might be worth trying a different recipe.

If you're having trouble with a cake not rising, try troubleshooting the possible issues listed above. If you've checked all of these and still can't figure out the problem, you may want to consult a baking expert or try a different recipe.