**
1 cup butter flavored shortening OR maybe 1 cup of butter. Or maybe, I'm thinking, one cup of each. Yeah, that would work.
*"*Wow, that's a lot of fat," a friend says to me after I confess to a baking marathon that featured one-and-half pounds of butter and one pound of butter-flavored Crisco.
"Well, the Crisco was trans-fat free," I retort snappily. Although how snappy can one be after spending three straight weekends in front of a cookie-packed oven? "And it was all in the interests of science."
She just looks at me. "Yeah, right," is written all over her face. I can read it clearly - it's written in capital letters.
Obviously, she doesn't appreciate chemistry at its finest.
*3/4 cup white sugar and 3/4 cup brown sugar. Doubled, of course, so that the same amount of sugar goes into the butter recipe and the trans-fat free Crisco recipe.
*
In late August, I was part of a panel about communicating chemistry at the national meeting of the American Chemical Society in Denver. I represented the poison part of the program. Popular Science columnist Theodore Gray showed videos of his Mad Science experiments, as an example, the flaming bacon lance, and don't miss the upcoming one in which he sets a tree on fire while trying to deep fry a turkey. McGill University's Joe Schwartz gave a rapid-fire tour of everyday chemistry questions - can copper bracelets treat arthritis? why can't you use fresh pineapple to make Jell-O? - the answers to which can be found here. There were ten of us, in all, including the session organization, ACS President-elect Bassam Shakashiri, who is so passionate about public engagement with chemistry that his website is actually titled Science Is Fun.
The last speaker was biochemist, food scientist, and cookbook author Shirley Corriher. And as you've probably already guessed, she talked about chocolate chip cookies. If you listen to her here, on an earlier NPR interview on the same subject, you'll catch that same fizz of enthusiasm that sent me home, inspired to bake.
2 eggs (for each recipe). In my kitchen, these are the cage-free, humane-certified, yes, I like chickens, kind of eggs. Just to let you know.
And I'd been thinking about the mystery of the cookie for a while anyway. My late Kentucky
grandmother made the best chocolate chip cookies known to humankind (yes, even better than your grandmother) and I'd never been able to recreate them. She *claimed *she just followed the recipe on the Toll House bag but I just knew there was some grandmotherly magic that she hadn't shared.
Two teaspoons vanilla extract.
And Corriher raised three points that I thought it would be fun to explore as a kitchen chemist:
The chemistry of butter gives it a lower melting point than shortening. That means that cookies made with butter spread out more rapidly. They're flatter and crisper. "If you want soft, fluffy cookies," she said, "then you want to try shortening." I was on that one.
The amount of protein in flour affects the texture of the cookie. And all wheat flours contain protein. When exposed to moisture and heat, the proteins break down to form a protein-composite called gluten. The more gluten the more elasticity and strength you'll find in the dough. So if you want a chewier cookie, you want a higher protein flour. For delicate and crumbly, a lower protein flour. As a general rule, cake flours contain about 8 percent protein and all-purpose flours between 10 and 12 percent.
A chocolate chip cookie recipe has very little liquid in it. What's there comes from the eggs, the water in butter or shortening, and the vanilla. So the longer the dough is left to sit, the more the liquids absorb into the flour and sugars. The dough is drier as the liquid soaks up, easier to handle, and - both chemists and professional bakers tell us- the flavors absorb more richly as well. In that earlier NPR interview, Corriher recommended up to 36 hours after mixing the dough before baking. Talking to me - and I suspect recognizing that I wasn't nearly patient enough to wait that long - she suggested 24 hours instead.
2 1/4 cups flour (at Corriher's recommendation I used a bread flour which is in the medium range of protein content)
I set up my experiment as follows:
Every Saturday morning for three weekends in a row, I made two batches of chocolate chip cookies. One was made with butter, one with butter-flavored shortening. I split each batch in two. I baked half of the dough immediately, saved the other half in the refrigerator, baked it the next day.
1 teaspoon baking soda, 1 teaspoon salt
And here's where I discovered the natural limits of the home experiment. I needed a polished test kitchen surrounded by chemists with measuring cups. Instead, I had a 17-year-old son who hated dark chocolate (milk chocolate chips, Mom!) and a husband who couldn't believe I'd consider anything but dark chocolate. ("Don't you think they're better with that contrast to bitter chocolate?" And back to the son ("Mom! Don't listen to Dad!")
Two cups of milk chocolate chips.
My son hates nuts. My husband prefers them in his cookies. They're in my test kitchen discussing the merits of the additives. I burn a batch. Just a little. My husband likes his cookies extra crispy. My son likes them on the still doughy side. I agree to leave out the nuts since I've ruined this batch of cookies for the teenage control group.
The debate continues. I continue baking cookies. The butter version goes into the red tin. The Crisco version into the blue - a completely scientific separation. Although not for long. As I said, I have a 17-year-old son. I was only grateful that he didn't inhale the dough in his spare time.
But here's the other problem with home test kitchen. The cook has a hidden agenda, that of recreating her grandmother's cookies. And about 100 or so cookies into the experiment, she realizes that these are too sweet. The overnighting of the dough does create more uniformly golden batches, yeah. But they're too sweet, too white sugary, too lacking in the faint tinge of caramel that colors my memory.
So I try:
1 cup brown sugar, 1/2 cup white sugar.
And then I try:
1 1/2 cups brown sugar.
And in the butter version of these cookies that last one comes pretty damn close.
I'm not sure I've discovered either the science or the art - and it's both, as any cook knows - of a perfect chocolate chip cookie. But chemistry of a childhood memory? I stand by the oven, breathing the buttery chocolate air of my childhood summers.
As I said, chemistry at its finest.
Final Recipe
- 1 cup butter
- 1 1/2 cups brown sugar
- 2 eggs
- 2 teaspoons vanilla extract
- 2 1/4 cups all-purpose flour
- 1 teaspoon baking soda
- 1 teaspoon salt
- 2 cups milk chocolate chips
- Preheat oven to 350 degrees F (175 degrees C). Grease cookie sheets.
- In a large bowl, cream together the butter and brown sugar. Add the eggs one at a time, beating with each addition, then stir in the vanilla .Combine flour, baking soda and salt; gradually stir into the creamed mixture. Finally, fold in the chocolate chips. Drop by spoonfuls onto cookie sheets.
- Bake for 8 to 10 minutes in the preheated oven. Remove cookies from hot sheets and allow to cool on a rack or board.
