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Speaker 1: Welcome to Brainstuff from how stuff works dot com where

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Speaker 1: smart happens him Marshall Brain And here's today's question. What

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Speaker 1: is baking powder and how does it work? Things like muffins, biscuits,

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Speaker 1: cakes and cookies usually use baking powder. What is the

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Speaker 1: baking powder doing. Baking powder is normally made of three

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Speaker 1: different parts, some kind of acid, some kind of basse,

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Speaker 1: and some kind of filler. All three need to be

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Speaker 1: dry powders that can be mixed together. For example, baking

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Speaker 1: soda is a base, cream of tartar is an acid,

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Speaker 1: and corn starch is a filler, and those are three

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Speaker 1: common ingredients. In school, you may have done the experiment

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Speaker 1: where you mix baking soda and vinegar a base and

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Speaker 1: an acid and get a bubbling reaction. Baking powder works

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Speaker 1: the same way. When you add water to baking powder,

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Speaker 1: the dry i acid and base go into solution and

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Speaker 1: start reacting to produce carbon dioxide bubbles. Single acting baking

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Speaker 1: powder produces all of its bubbles when it gets wet.

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Speaker 1: Double acting baking powder produces bubbles again when it gets hot.

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Speaker 1: If you want to prove to yourself that this is

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Speaker 1: how baking powder works, simply try mixing a teaspoon of

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Speaker 1: baking powder into a cup of hot water. As long

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Speaker 1: as the baking powder is fresh, you will definitely see

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Speaker 1: the reaction. Many recipes call simply for baking soda rather

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Speaker 1: than baking powder. Usually these recipes use some kind of

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Speaker 1: liquid acid like butter, milk or yogurt to create the

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Speaker 1: reaction with the baking soda to produce the bubbles. The

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Speaker 1: reason why people often prefer baking powder to yeast is

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Speaker 1: because yeast takes so long, usually two to three hours

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Speaker 1: to produce its bubbles. Baking powder is instant, so you

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Speaker 1: can mix up a batch of biscuits and eat them

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Speaker 1: fifteen minutes later. Now they understand how baking powder works,

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Speaker 1: you can understand two things that you often see in recipes. First,

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Speaker 1: many recipes instruct you to mix all of the dry

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Speaker 1: ingredients together and then add the liquid that keeps the

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Speaker 1: baking powder from reacting until the end of the mixing process. Second,

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Speaker 1: many recipes tell you to mix only briefly, just until

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Speaker 1: the ingredients are moistened. That minimizes the escape of the

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Speaker 1: gas from the batter. If you were to stir for

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Speaker 1: a long time, the reaction would end in the stirring

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Speaker 1: would have allowed all the bubbles to escape. Do you

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Speaker 1: have any ideas or suggestions for this podcast? If so,

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Speaker 1: please send me an email at podcast at how stuff

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Speaker 1: works dot com. For more on this and thousands of

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Speaker 1: other topics, go to how stuff works dot com