We our project we chose to investigate the chemistry of how heat affects the baking of the brownie. Since there were a variety of ways to make brownie's, we wanted to stick to the basics for all three experiments (flour, sugar, cocoa powder, butter, eggs) to produce some conclusive results with these experimental constants. We felt as though having more complicated ingredients would complicate the results so we decided to go with the essentials.
Science of the Brownie
Before we get to the heating aspect of baking the brownie, we have to understand what goes on before its even put in the oven. One of the steps involves beating the eggs until in become the same texture throughout. Beating the eggs is necessary because when their beaten the proteins within the egg eventually denature which undo the amino acids within the eggs. When mixing all the dry materials together will first start out as a heterogenous mixture but hen mixed thoroughly together it will become a homogenous mixture. Baking soda in of itself has the chemical formula of 2NAHCO3. This baking soda produces the essential carbon dioxide (but also produces water) that gives the brownie it's fluffy texture. Although not directly involved with our experiment, the cocoa powder that is used came to be because the cocoa butter (from the cocoa bean) was extracted leaving just the powdery substance. This butter is polymorphic (Meaning it be in two different crystal forms of the same substance) so while its being heated it becomes a liquid but when made to dry it becomes solid again. But because its polymorphic, it can be both at once. But finally, depending on how much heat is applied (along with the time in which its allowed to react that heat)to the solution it's texture could be soft, corse and firm. And that is what our experiment is here to test today.
Experiment and Results
The one variable we decided to use in this experiment is heat.,all other ingredients were kept constant including the batter and amount of time kept inside the oven.
Dry Ingredients
- 1 cup (200g) granulated sugar
- ⅓ cup (40g) unsweetened cocoa powder sifted
- ½ cup (64g) all-purpose flour
- ¼ tsp salt
- ¼ tsp baking powder
- ½ cup (113g) of melted butter (Keep aside to cool)
- 2 eggs room temperature
- 1 tsp. McCormick Vanilla
- ¼ cup of water
Wet Ingredients
Trial 1
For this first trial we decided to turn the oven onto 280 degrees to test how well the brownie would develop. This Brownie didn't develop enough to be considered a brownie, it was too mushy and didn't have the correct texture. It tasted like plastic and only had one rubbery texture throughout.
Trial 2
This trial ended in a different result that could be considered a "good" brownie. we started the oven at 350 degrees it wasn't the best in our opinion, it was supposed to be the median of the experiments but fell short by a few components. It was easy to peace buts till contained that rubber texture the previous experiment had. The inside didn't retain the heat of the oven for very long so the taste was affected by that as well.
Trial 3
The last trial we decide to attempt was turning the oven heat all the way up to around 420 degrees. The brownies were burnt around the edges but surprisingly tasted the best out of the experiments. It had a difference of texture from the outside compared to the inside, but it was warm and we noticed the smell was much stronger as well.
In conclusion we learned that heat has an astronomical affect on how brownies are made. Putting in the oven with 280 degrees of heat would make them too soft and tasteless, it took much longer for these brownies to solidify and have that defining shape. Leaving it in for 350 degrees wasn't exactly the target temperature either (as suggested) because although it had a more firm texture than the last, there was no improvement in the taste either. Admittedly enough it came along with its formation nicely but the inside of the brownie ended up being just short of where it needed to be. Lastly for 420 degrees, it may have been too excessive to apply this much heat but it did serve as having the most firm texture but also having the best taste and strongest smell as well. As it was baking, I noticed that even after it had formed it was also important that the heat gets inside the brownie so that texture and heat is having its effect throughout. The more heat that is applied to these brownies the faster it will take for the brownies to develop. As we mentioned earlier, that carbon dioxide is responsible for a lot of the lightness and soft texture that is present in these brownies. Its apparent that the more heat is added the quicker these carbon dioxide molecules react and if at all too much heat is added they will eventually become rough and course which is why a perfect balance of heat and time is required.
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