Baking soda is a natural alkaline ingredient activated by liquid and acid.
Naturally acidic ingredients that will activate baking soda:
There must be some acidic ingredient in the recipe for baking soda to function. Baking soda begins to leaven as soon as it touches liquid so if you wait too long before baking you may notice a decrease in leavening effect. If you use too much baking soda, you may taste an unpleasant metallic flavor in your food. Baking soda also helps add a beautiful browned color to baked goods by elevating pH levels.
Since baking soda must be fresh to work properly, it’s important to switch out your container before the expiration date. However, baking soda can loose its effectiveness even before that date.
Test for freshness
Placing 1 teaspoon of baking soda in a bowl and pour 1 teaspoon of distilled vinegar on top. If the baking soda immediately bubbles violently, it is fresh. If nothing happens, throw away the baking soda and buy a new one.
Baking powder is a combination of baking soda, acid, and cornstarch. Most baking powder available in the market today is double acting, (meaning its first reaction occurs when combined with liquid to help aerate the batter or dough and a second more slow-acting reaction occurs when heated in the oven). Unlike baking soda, baking powder doesn’t require an acid to activate, only moisture, and baking powder batters can be made ahead of time due to that double acting property.
Test for freshness
Place 1 teaspoon of baking powder in a bowl with 1 cup of hot water from the tap. If it bubbles up, the baking powder is fresh. If nothing happens, throw the baking powder away and buy a new container.
It’s important to understand that baking soda is four times stronger than baking powder. This means 1 teaspoon of baking powder will raise a cup of flour, whereas only a 1/4 teaspoon of baking soda can produce the same effect. Knowing what each leavener requires to function and the strength of each does make it technically possible to substitute baking soda for baking powder, however the reverse is not true. Either way, I do not recommend attempting any substitutions because it is complicated and may ruin your baking project. Plus, both ingredients are so cheap and readily available!
Some recipes call for both baking soda and baking powder in order to have the highest effect of acid neutralizing and leavening powers .This works especially well for acidic dough that needs to be stored overnight.