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Chemistry of Cooking: Crème brûlée
Transcript of Chemistry of Cooking: Crème brûlée
Add the vanilla bean and its residue, along with the quart of heavy cream, into a saucepan at medium heat, stirring slowly. After bringing the homogenous mixture to a boil, remove from the heat and cover the saucepan for 15 minutes. Extract the vanilla bean and add to a container of sugar to dust the ramekins with later.
Separately, whisk together the 1/2 cup of sugar and the 6 egg yolks until well blended. Slowly add in the cream from stage 1, being careful not to cause extensive clumping. Strain the final mixture to eliminate any clumps.
1 Quart Heavy Cream
1 Vanilla Bean
1 Cup Vanilla Sugar
6 Large Egg Yolks
2 Quarts Hot Water
Fill the ramekins with the mixture and carefully position them inside a roasting pan. Subsequently, pour hot water into the pan. Bake for 42 minutes, and follow with 2 hours of refrigeration.
Preparation: 15 Minutes
Cook Time: 60 Minutes
Baking time: 45 Minutes
Remove the ramekins and roasting pan from the refrigerator and let thaw for 30 minutes. Add a thin layer of sugar to the top of the crème brûlée. Melt the sugar to create the crispy top by applying the heat from the torch in circular motions. Wait 5 minutes for the brûlée to harden before serving.
Caramelization of Sugar
C12H22O11, Sucrose (disaccharide)
½ fructose (C6H12O6)
½ glucose (C6H12O6)
C6H12O6 + C6H12O6 => C12H22O11 + H2O
Another one of the chemical reactions that occur during this baking process happens when making the hard sugar top by applying the heat from the propane torch to the villain sugar. Because the sugar is disaccharide, glucose (C6H12O6) and fructose (C6H12O6) as well as water is produced once the sugar is exposed to the high temperatures. As the heat continues to be applied the water evaporates into steam and the food is able to reach 160 degrees Celsius enabling it to caramelize. Particles continue to heat up and break up into smaller fragments; molecules form new compounds resulting in a change of color and flavor. If the substance continues to heat after all the water is evaporated it will burn, forming carcinogens.
During the baking of the mixture situated in the ramekins, several different chemical reaction occur in order to cook the custard. Principally, the maillard reaction which takes place between the amino acids of the egg yolk and the reducing sugars from the sugar we added is what causes the cooking. As the 325ºF heat from the oven was applied, a reactive portion of the sugar combines with the amino group of the amino acid to form a series of "poorly characterized" molecules (glycosylamine and aminoketose) to result in a final, cooked morsel.
Picture from FoodNetwork.com