I find that sodium bicarbonate ruins the taste of many cakes and cookies. If I'm using double acting baking powder, do I need to add the sodium bicarbonate as well? I have come accross so many recipes that require both ingredients.
If the recipe calls for both (and it's a good recipe), it actually needs both. A common reason is that the baking powder provides leavening and the baking soda helps neutralize a bit of the acid.
It's a little surprising you're finding that baking soda ruins the taste and not baking powder; baking powder contains baking soda. I wonder if "ruins the taste" is an exaggeration or if you had a bad experience with baking soda and are a little more sensitive to it now. But if it's really ruining the taste, it's just a bad recipe. There are a couple possibilities:
- the total amount of chemical leavening is too large in the recipe (it doesn't matter whether it's soda or powder) - make sure teaspoon hasn't been changed to tablespoon by accident!
- there's not enough acid in the recipe to react with the baking soda so you actually have baking soda left over
The answer is: "It depends."
Baking soda requires an acidic ingredient to leaven foods, but baking powder has the acid already added. Some recipes will use both if there is an excess or acid in the dough/batter that can be used by baking soda to rise more.
If you find that the taste of baking soda ruins your dishes it's probably that you didn't have enough acid to neutralize it or you're using too much.