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Weigh it out: the cookie experiment, part I

March 20, 2013

A few months ago, I got a new cookbook and was delighted to find that the author included weights for all of her dry ingredients. While measuring dry ingredients by weight is de rigeur in Europe, it’s somewhat uncommon in the US.

But as a chemist, weighing my dry ingredients rather than measuring them by volume is almost second nature. In the lab, we always measure powdered chemicals by weight, because their volume can vary a lot depending on how tightly they’re packed!

This isn’t something that we usually worry about too much in the kitchen, but it can make a big difference. So, my lab-mate Tracey and I recently did a little kitchen experiment to demonstrate how much different measuring techniques can affect the final properties of a dish.

We chose to study chocolate chip cookies, because really, who doesn’t like cookies? (Also, we were sort of inspired by this experiment). The idea behind the experiment was simple: make three batches of cookies, and measure the same volume of flour by different methods in each batch.

In one batch, we would sift the flour; in another, we’d scoop it like normal, and in the third we’d pack it tightly in the measuring cups. We hypothesized that sifting the flour would give us much less flour (by weight) while packing it would give us much more. We also hypothesized that the amount of flour in the cookies would affect their texture, with more flour leading to dryer, denser cookies.

Clearly, this is important research, necessary to baking enthusiasts everywhere, right? Good – glad you agree! Without further ado, I’ll walk you through our procedure and our results… it’s like a lab report, but way tastier 😀

Tracey is ready to make some cookies - are you?

Tracey is ready to make some cookies – are you?

Procedure:

We based our recipe on the classic Nestle Toll House chocolate chip cookie recipe, halved so that we would end up with a reasonable number of cookies.

The overall ingredient list for each batch was:

  • 1 c. + 2 Tbsp flour
  • 1/2 tsp. baking soda
  • 1/2 tsp. salt
  • 1/2 c. (1 stick) butter, softened in the microwave
  • 3/8 c. granulated sugar
  • 3/8 c. packed brown sugar
  • 1 tsp. vanilla extract
  • 1 egg
  • 1 c. chocolate chips

To make three comparable batches of cookies, we began by measuring out 1 ⅛ c. granulated sugar (weight: 233 g) and 1 ⅛ c. packed brown sugar (220 g) in a single bowl. After mixing thoroughly, we used a kitchen scale to divide the sugar mixture into 3 equal (151 g) portions.

1 c. and 2 Tbsp. of granulated sugar weighed 233 g (yes, the scale was tared with the measuring cup/spoons already on it).

1 c. and 2 Tbsp. of granulated sugar weighed 233 g (the scale was tared with the measuring cup/spoons already on it).

Using 3 separate bowls, we creamed 1 stick of unsalted butter into each aliquot of sugar (yes, I really did just use “aliquot” to refer to sugar). Tracey did the final mix in each bowl to ensure uniform consistency. We then added 1 tsp. vanilla extract (okay, maybe a little more, because we like vanilla) to each bowl of sugar/butter mix & stirred until just combined. Finally, we added 1 grade A extra large egg to each bowl & mixed well.

We weighed out three 1 c. + 2 Tbsp. portions of flour. In Batch 1, we sifted the flour through a fine-mesh sieve and scooped it gently into our measuring cups. In Batch 2, we scooped the flour straight from our storage bin into the measuring cups. In Batch 3, we packed the flour into our measuring cups. These methods resulted in significantly different weights of flour in each batch of cookies (116, 141, and 177 g, respectively), as reported in Figure 1.

Mass of flour measured by different methods in the chocolate chip cookie experiment.

Mass of flour measured by different methods in the chocolate chip cookie experiment. Packing resulted in a 50% increase in the amount of flour used compared to sifting.

We then combined each portion of flour with ½ tsp. baking soda and ½ tsp. salt and mixed thoroughly. Each flour mixture was then added to one of the sugar/butter mixtures and stirred thoroughly. Finally, we added 175 g (approx. 1 cup) chocolate chips to each bowl and stirred to combine.

We placed single scoops (1.5 Tbsp.) of cookie dough onto a parchment paper-lined cookie sheet and baked for 10 minutes at 375 F. We then removed the cookies from the oven and let them cool 2 minutes on the pan before transferring to a wire cooling rack.

We observed the appearance of the cookies and sampled each type of cookie both warm and after cooling 1 hour. We then baked the rest of the cookies and took them to different Super Bowl parties the next day and asked our friends to rate the cookies from favorite to least favorite.

Results

So, I’m actually going to break this up into two posts and tell you about the results on Friday.  (I know, I know, how can I leave you hanging when there are cookies on the line?)  But, in the meantime, perhaps you’ll enjoy some of the photos we took to… uh… document our procedure?

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