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As described here, most common baking powders contain two acids, one that reacts to moisture, and one that mostly reacts when heated. Does that mean that if my dough is already acidic (and has no baking soda to neutralize said acid), all the baking soda in the baking powder will get used up when mixed with the wet ingredients, leaving none for the second reaction during heating?

If so, what rules can I follow to make sure that my dough/batter has a neutral pH and will therefore get that second rise? How much baking soda would be needed to neutralize certain amounts of acidic ingredients like buttermilk, sour cream, cocoa, honey, vinegar, lemon juice, molasses, etc?

EDIT: I'm using Magic Baking Powder by Kraft Canada, which consists of cornstarch, monocalcium phosphate, and sodium bicarbonate.

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2 Answers 2

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The short answer to your question is YES. The extra acid in the ingredients will hamper the second act of the double acting baking powder. The acids are timed/staged for reaction not the baking soda.

The Magic Baking Powder (happens to be in our kitchen, too) is mostly a single acting formula since monocalcium-phosphate is a low temperature acid (with apparently some double acting properties due to generation intermediate step of dicalcium phosphate; per your link). High temperature acid for second acts typically include sodium aluminium sulfate, sodium aluminum phosphate and sodium acid pyrophosphate.

You can try to counteract that by adding a bit of baking soda, but you run the risk of altering the taste and not having it all neuralized.

If you really want to get pedantic, use a pH meter to measure the acidity of your dough. I suspect tasting the dough might give an indication as well. (bitter alkaline, sour acidic)

Another test might be to mix your acidic ingredients in a bowl with some water and start adding measured baking soda until you see no more reaction (bubbles) and use that as a your basic of neutralizing your dough.

All said and done, I agree with SAJ14SAJ that you'll be just fine going with the existing recipe. There should be enough baking soda left to get something out of your double act. I also heard it from a world-class baker that most recipes can be done with only baking soda, let alone baking powder or double acting ones.

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I wouldn't rely too much on tasting. Sugar will cover both the sour taste of the acid and the soapy taste of the base. –  rumtscho Apr 18 '13 at 18:13
    
@rumtscho yes it does, and thanks for pointing it out. hopefully roughly equally on both sides and enough to give a hint. –  MandoMando Apr 18 '13 at 18:30
1  
I also found this: clabbergirl.com/faq.php: "Due to the nature of how this acid [monocalcium phosphate] releases carbon dioxide gas with sodium bicarbonate in the presence of moisture, two-thirds of the available gas is released within approximately two minutes. It then becomes dormant at room temperature due to the generation of an intermediate form of dicalcium phosphate during the initial mixing. This stage of the reaction contains only one hydrogen ion and requires the catalyst of heat above 140 degrees F. in the batter." But the extra acid will still use the alkaline I expect. –  Hinrik Apr 18 '13 at 18:34
    
@Hinrik nice find. I've updated the answer to note that monocalcium phosphate is a low temperature acid. –  MandoMando Apr 18 '13 at 18:46

More technically, baking powder reacts a basic ingredient or alkali with an acidic ingredient. The reaction is enabled by the presence of water or heat. In a double acting baking powder, the 2nd reaction requires a certain amount of heat to be triggered, but it is still a reaction between an acid and a base.

So the limiting factor is whichever of the acidic or basic ingredient there is less of.

For example, if you added more lemon juice to a quick bread based on baking powder, there would just be a surplus of acid. If you add more baking soda to a balanced bread, there would be an excess of base (which would also taste a little metallic, as baking soda tends to).

However, there is no need to get the two ingredients perfectly balanced; that is just an incorrect supposition. Many or even most baked goods are probably a little bit acidic from fruit, buttermilk, or other ingredients, even after they are baked. If you look at a chart showing the pH of common ingredients, you will see that most are slightly acidic, such as flour and butter, even when you wouldn't expect it.

Update:

Per Harold McGee in On Food and Cooking, 2004 edition, pp. 535:

A rule of thumb for balancing baking soda and acid is 1/2 teaspoon of baking soda to:

  • 1 cup of fermented milk
  • 1 teaspoon lemon juice or vinegar
  • 1 1/4 teaspoons cream of tartar
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I'm not sure whether you answered the question. My concern is the 2nd reaction. Yes, it's still the same kind of reaction between an acid and a base. But if, as I posited earlier, the batter is already quite acidic (and includes no baking soda) before the 1st reaction happens, won't the 1st reaction use up all the alkalines in the baking powder, leaving nothing left for the 2nd reaction to happen? If true, then baking powder won't behave any differently than pure baking soda in particularly acidic recipes from a leavening standpoint (aside from requiring more of it). –  Hinrik Apr 18 '13 at 17:44
    
You will be fine... almost all recipes have an excess of acid. –  SAJ14SAJ Apr 18 '13 at 17:45
    
But how does that work? It would make sense to me if it were the alkalines in the baking powder which would only react when heated. As long as there's more acid left in the batter, what would prevent all the alkalines in the baking powder from reacting when exposed to moisture? Why would there be anything left for the 2nd reaction? –  Hinrik Apr 18 '13 at 17:54
    
That is an interesting question, and I am having hard time finding the exact chemical constituents of a particular baking powder--and the thing is, they all vary. Still, I can tell you from 30 years of experience, in practice it is not an issue, even if it should be in theory. What brand of baking powder (from what country) are you using? –  SAJ14SAJ Apr 18 '13 at 18:08
    
I'm not having any issues with the recipes I'm using, it's just something I've been wondering about. I've been using Magic Baking Powder by Kraft Canada, which is composed of corn starch, monocalcium phosphate, and sodium bicarbonate. Don't know the exact ratios, though. –  Hinrik Apr 18 '13 at 18:19

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