My Bubbles!

I realized that the video I posted yesterday begged the question, “why are there bubbles in my pancakes?”. It included an interview with a student who said they learned why this happens, but never actually got around to an explanation.
I think everyone should know why pancakes have bubbles. I mean, we all know that the words “fluffy” and “pancake” were meant to be together, like in this recipe for the best pancakes ever:

We are fluff.

So, the first thing about this recipe that might strike you as odd is that it contains vinegar. It also contains baking powder and baking soda, ensuring that this batter is in for some serious puffiness once it hits the griddle.

Vinegar, as a molecule, looks like this in 2-D or this in 3-D. It’s chemical formula (C2H4O2) tells us that there are 2 carbon atoms, 4 hydrogen atoms and two oxygen atoms. As you probably know from it’s pungent, sour taste, vinegar is an acid. In fact, it’s also called Acetic Acid. Why would you want a yucky, sour acid in your pancakes?

Answer: to react with the yucky, bitter bases (baking soda and baking powder) that also go in the batter. Baking powder is just baking soda, plus a powdered acid, plus a starch. It was invented to eliminate the need for at-home cooks to add their own acid, like you need to with baking soda. The acid and base that make up baking powder only react once they’re mixed with a liquid, and the starch is in the mix to absorb any moisture that might be in the container. That begs the question: what’s baking soda?

Baking soda, also known as sodium bicarbonate (NaHCO3) goes through a reaction that releases a gas, carbon dioxide. No, not carbonĀ monoxide, the silent killer (although you should have a detector for this gas in your house). The gas produced when you’re making pancakes has an extra oxygen atom, and won’t hurt you or your pancakes. But it does make bubbles. Unfortunately, the reaction also produces a strong base, which would make the batter taste bitter. Adding the vinegar results in what’s called a neutralization reaction. The reaction both breaks the baking soda into molecular pieces (sodium, water and carbon dioxide), and balances out the flavor of the base. This produces delicious pancakes with a fluffy disposition, (which can be emphasized by drawing a smiley face on them with whipped cream, which I strongly encourage).

I bet you’re wondering how “carbon dioxide” translate into “bubbles.” When you heat up your pancake batter, all of the atoms start to move around a lot more than they do at room temperature. Just think, if someone dropped you onto a hot griddle, you’d probably start shifting around pretty quick, too. You’d probably hop from foot too foot, faster and faster, until you jumped right off the griddle. That’s essentially what the atoms that make up the carbon dioxide atoms are doing. They’re getting hotter and more energetic, and but they run into the batter. The atoms are flying around like crazy because it gets rather warm inside the pancake, and they can’t escape. The bubbles are the result of the gas atoms looking for a way out. They push against the batter more and more the hotter it gets, expanding until visible pockets of air form.

As you can imagine, the more of these leavening agents (baking powder and baking soda) you add to a mixture, the more carbon dioxide will be produced, and the more bubbles will form. These pancakes haveĀ both ingredients, and are therefore especially fluffy.

For more information on how pancakes work, check out this article from Serious Eats. Actually, pretty much everything on Serious Eats is worth checking out, just FYI). So is this rap video about making pancakes:

As my first time explaining chemistry, I might need some tips! Leave comments if I left something important out, or if there’s something else you want me to talk about : ) I look forward to answering questions,

Till next time,



One comment

  1. Jessica says:

    I love that your chemistry blog is also your food blog.

    Here’s a question for you: why does apple cider go hard in my fridge?