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Kitchen Chemistry: Baking Powder

Today we discuss the leavening agent, baking powder. Simply put acids and bases react with one another to create volume and lighten texture. Come see what’s in the doctor’s kitchen for a kitchen check up. Now take a deep breath, don’t get your blood pressure up. It will all make sense soon. You may notice there is a “double acting” quality on certain baking powders. Ever wonder what that was about? Well inquiring minds need to know…

So what exactly is “double acting” baking powder?

The powders are made from baking soda (sodium bicarbonate) and one or more powdered acids. Below is an example of a particular brand.

One acid (Monocalcium phosphate) reacts immediately when added to water, the acid then combines with the baking soda to create carbon dioxide gas.

That’s:

Monocalcium phosphate + water combined with baking soda = carbon dioxide gas.

The other acidic powder, in this case is sodium aluminum sulfate, which slowly reacts at room temperature. However, it also reacts much MORE when heated ( during the process of baking). This allows more time for a batter to be mixed before baking as the agent still will react in the baking process. The cool thing is, the gases lost as the batter is prepared BEFORE baking are replaced as it cooks in the oven. The acid activated by heat reacts at 140 degrees F and above.

You may have noticed another ingredient on the label of the can in the photo above. Yes, it is cornstarch. Well, the function of cornstarch in this mixture is to prevent a premature reaction of the acids and to absorb moisture.

So lets review: acid 1 is fast reacting and acid 2 is slow reacting plus has qualities to react when applied to heat. Make sense?
Baking powders that contain both fast- and slow-acting acids are double-acting. Then we have those that contain only one acid, which are single-acting. The benefit of being able to rise twice is that it increases the chance of baked goods rising properly by rendering the time elapsed between mixing and baking less critical. Hey, don’t we all just want to be more successful.
Common acid salts:

1. cream of tartar

2. monocalcium phosphate

3. sodium aluminium sulfate

4. sodium aluminum phosphate

5. sodium acid pyrophosphate

Well, I hope I haven’t lost you, hold tight. Guess what? You can also create a baking powder. Yes, that’s right. Ever have a moment where you don’t have baking powder? Well, with two parts cream of tartar (tartaric acid) and one part baking soda. Voila, You have baking powder.

So for 1 tsp that would be:
1/2 teaspoon of cream of tartar + 1/4 teaspoon baking soda.

Baking powder gives baked goods volume even in the absence of acid in the recipe itself. It does so by carbon dioxide formation when the baked good is heated.

Ever try to figure out how much baking powder to use in a recipe? A general rule of thumb is approximately 1 to 1 ¼ teaspoon of baking powder to 1 cup flour. If too much is used in your recipe, this produces larger bubbles that will rise to the surface and deflate leading to a heavy or sunken end result.

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