National Chemistry Week - Experiments - A Chemical Engineer’s Recipe for Chocolate Chip Cookies

Materials:

  • 236.6 cm3 (250 mL) partially hydrogenated tallow triglyceride (butter or margarine)
  • 177.45 cm3 (177 mL) crystalline sucrose (sugar)
  • 177.45 cm3 (177 mL) unrefined sucrose (brown sugar)
  • 4.9 cm3 (5 mL) 4-hydroxy-3-methoxybenzaldehyde (vanilla)
  • 2 calcium carbonate-encapsulated avian albumen-coated protein (eggs)
  • 532.35 cm3 (500 mL) gluten (flour)
  • 4.9 cm3 (5 mL) sodium chloride (salt)
  • 4.9 cm3 (5 mL) sodium bicarbonate (baking soda)
  • 1 package of theobroma cacao (chocolate chips)
  • 236.6 cm3 (250 mL) chopped de-encapsulated legume meats (nuts-optional)

Procedure:

  1. Cream the partially hydrogenated tallow triglyceride, methyl ether of protocatechuic aldehyde, crystalline and unrefined sucrose in a bowl.
  2. Add the calcium carbonate-encapsulated avian albumen-coated proteins and mix well.
  3. In a separate bowl combine the gluten, sodium chloride, and sodium bicarbonate. Add to creamed mixture.
  4. Stir in theobroma cacao and de-encapsulated legume meats.
  5. Place the final mixture piecemeal onto a cookie sheet.
  6. Heat in an 463 K oven for 0.13 to 0.16 hours and allow the chemical reactions to take place.
  7. Remove from oven and place on cooling rack.

Ingredients / In Chemistry Speak
sugar / Sucrose
brown sugar / Unrefined sucrose
butter / partially hydrogenated tallow triglyceride
egg / calcium carbonate-encapsulated avian albumen-coated protein
vanilla / 4-hydroxy-3-methoxybenzaldehyde or
methyl ether of protocatechuic aldehyde
all-purpose flour / Gluten
baking soda / Sodium bicarbonate (NaHCO3) (base)
salt / NaCl
semi-sweet chocolate chips / theobroma cacao
Chocolate Chip Cookie Lab Work Name:______
Directions / The Chemistry of It
Preheat oven to ______degrees / Changing temperature changes the ______energy of the particles in the mixture.
Steps 1 &2 / Only ______changes.
Step 3 / You add flour late in the process so that you won't "work" the dough for too long, keeping the gluten complexes small.
Step 4 / Definitely a ______mixture.
Step 5: Drop dough by rounded tablespoonfuls 2 inches apart onto cookie sheet. / Size matters. CO2 bubbles form throughout the entire cookie. Only the outside gets hot enough to caramelize.
Step 6: Bake _____to______minutes or until light brown. The centers will be soft. / When the batter heats up, the sucrose (sugar) breaks down into glucose and fructose, forming a polymer chain, giving the cookie its light brown, shiny crust. When sodium bicarbonate (baking soda) heats up, it causes a chemical reaction: 2NaHCO3+ Na2CO3 + H2O + CO2. The CO2 gas that's formed makes the "bubbles" in the cookies. NaCl (salt) keeps the bubbles from getting too big by slowing the production of CO2. The fat (butter) keeps the flour from forming an overly extensive network of gluten, giving the cookie a lighter texture. The fat and protein (egg yolk) hold the dough together and the albumin (egg whites) support the bubbles.
Step 7: Remove from oven and let cool for one minute. Remove from cookie sheet and place on wire rack to finish cooling. / Cooling allows caramelizing to be completed and allows structure developed by gluten and egg to set.