T (age 14), and I watched a Thanksgiving themed chemistry demonstration by Professor Diane Bunce, linked through Time Magazine's website, yesterday afternoon. T, was very taken with the make-the-Ziploc-baggie-expand-and-possibly-explode-with-vinegar-and-baking-soda type experiment that Professor Bunce used to explain why you should not over mix muffin batter.
I was more intrigued with her explanation, that over-stirring the batter would cause all the carbon dioxide bubbles, formed by the combination of baking powder and the lactic acid of the milk, to pop prematurely, releasing the gas, and keeping the muffins from rising as well during baking. That sounded like a good experiment for Science Sunday, and a good way to get a jump on Sunday morning's breakfast at the same time.
First, I watched "The Magic School Bus Ready, Set, Dough" with the younger children (with no exploding baggies to be seen, T excused himself), to review baking soda, or baking powder's role in causing dough to rise (click the link above to view the episode).
Then, I pulled out all the ingredients for making muffins. I pointed out to the girls (ages 5 and 6) how the recipe called for mixing the dry, and wet ingredients separately, and combining them, stirring just until the dry ingredients were moist.
Keeping Professor Bunce's theory in mind, I gave the girls two bowls, each with a half teaspoon of baking powder, the leavening agent in the muffin recipe, and about a tablespoon of milk, the activating acid from the recipe.
With the first bowl of milk, I instructed them to only mix the baking powder in enough to get it wet. But, with the second bowl, I had them stir like mad. As expected, the first bowl rose in frothy bubbles, while all the bubbles in the second bowl rose to the top, and popped.
Then we mixed up the muffin batter...
...combining the dry and wet ingredients together...
...and being careful not to over stir the batter.
After we filled one muffin tin...
...we took the small bit of remaining batter, and stirred it a good deal more...
...before dividing it into another pan, and popping it into the oven as well. The girls entertained themselves with vinegar and baking soda experiments...
...while the muffins rose, and baked.
And, I do mean rose and baked. In fact, the over mixed muffins (like the one pictured on the left, below) rose even better than those with the less stirred batter.
So, we turned to Alton Brown, as I've said before - our favorite kitchen scientist, and the episode of Good Eats entitled, "The Muffin Method Man", in which Mr. Brown explains, that over stirring muffin batter can lead to large bubbles of carbon dioxide, instead of small ones, and result in tunnelling, or big holes inside the muffins.
That would certainly be consistent with what we saw when we stirred the baking powder and milk. Take a look at the big bubbles on the left, verses the small frothy bubbles on the right.
The only problem is when we cut the muffins open, the over mixed muffin really looked less hole filled than the first batch of less stirred muffins. I might not enter them in a county fair, but I wouldn't be embarrassed to serve them to company.
...if there were any left that is.
But I'm sure conventional wisdom, and high school home economics teachers everywhere, cannot be wrong. There simply must be a good reason not to over mix the muffin batter. Clearly, we need to experiment more. It's a good thing the children like muffins for breakfast.
While I'm out picking up extra muffin add-ins, click over to the Science Sunday link-up hosted at Adventures of Mommydom, for more science themed, and maybe even calorie free, family fun.
It's great to be a homeschooler.