Making a Caramel Cake
Preview of “Chemistry and Physics of Cooking,”
CHEM 89
Scheduled to be taught Spring 2013
at Duke University
By Professor Patrick Charbonneau, Chef Justine de Valicourt,
With teaching fellows Keely Glass and Mary Jane Simpson
First ingredient: Flour
http://www.killerbunniesinc.com/2011/02/dry-dock-farm-whole-wheat-flour/
Disulfide bonds form sticky dough and
crusty bread
http://en.wikipedia.org/wiki/File:Cystine-skeletal.png
http://www.thekitchn.com/how-can-i-get-my-pizza-dough-t-150596
http://biology.clc.uc.edu/fankhauser/cheese/pane_rustica/pane_rustica.htm
Low protein flour does not form as
many disulfide bonds, so it makes a
more tender cake
http://goboldwithbutter.com/?p=257
Flour names and protein content
http://www.kingarthurflour.com/flours/cake-flour.html
King Arthur Queen Guinevere Cake Flour (8.0%)
King Arthur Round Table Pastry Flour (9.2%)
Caputo 00 Extra Blu Flour (9.5%)
Generic All-Purpose Flour (10.3%)
King Arthur All-Purpose Flour (11.7%)
Caputo 00 Pizzeria Flour (12.0%)
General Mills Harvest King Flour (12.0%)
Robin Hood All-Purpose Flour (12.0%)
King Arthur Bread Flour (12.7%)
Bob's Red Mill Semolina Flour (12.9%)
Five Roses All-Purpose Flour (13.0%)
Eagle Mills All-Purpose Flour (13.3%)
King Arthur Whole Wheat Flour (14.0%)
King Arthur Whole Wheat Organic Flour (14.0%)
King Arthur Sir Lancelot Flour (14.2%)
Arrowhead Mills Vital Wheat Gluten Flour (65.0%)
Hodgson Mill Vital Wheat Gluten Flour (66.6%)
Bob's Red Mill Vital Wheat Gluten Flour (75.0%)
Gillco Vital Wheat Gluten Flour (75.0%)
King Arthur Vital Wheat Gluten Flour (77.8%)
http://www.thefreshloaf.com/node/22310/high-gluten-wheat-flours-amp-gluten-percentage-table
Solid fat melts and leaves air bubbles
to make a light texture
http://bakingbites.com/2009/07/can-you-over-soften-butter/
http://sustainableecho.com/soft-butter-spread-recipe/
http://www.braisingcain.com/2011/04/06/caramelized-shallot-butter/
Gently mix flour and butter to avoid
popping air bubbles or forming
disulfide bonds
http://www.greatvectors.com/2011/03/blue-bubbles/
http://en.wikipedia.org/wiki/File:Cystine-skeletal.png
Baking
1. Expansion – 140 °F, 60 °C, 333 K
2. Setting
3. Browning
Acidic buttermilk liberates carbon
dioxide from baking soda, and hot gas
expands
• Baking soda + Buttermilk =
http://www.greatvectors.com/2011/03/blue-bubbles/
http://www.apartmenttherapy.com/the-miraclecleaner-baking-soda-tips-tricks-for-using-bakingsoda-around-the-home-164996
http://consumer.darigold.com
/Lowfat-Buttermilk-8oz.html
http://en.wikipedia.org/wiki/Lactic_acid_bacteria
Bacteria consume lactose and
form lactic acid
Baking
• Expansion
• Setting – 180 °F, 82 °C, 355 K
• Browning
Setting: forming a solid cake
• Starch absorbs water – cake starts to dry out
http://www.sciencedirect.com/science/article/pii/S0032591001004004
• Egg proteins denature, then coagulate – provide
solid structure
http://cdavies.wordpress.com/tag/coagulation/
How long should I cook the cake?
• How long does a 6 cm spherical cake take to
cook? The oven is 400 °F (204 °C, 477 K) and
cake needs to set (180 °F, 82 °C, 355 K).
L
http://www.dailyunadventuresincooking.com/2009/08/chocolate-coconut-zucchini-cupcakes.html/
Cook time is based on principles of
diffusion
• How long does a 6 cm spherical cake take to
cook? The oven is 400 °F (204 °C, 477 K) and
cake needs to set (180 °F, 82 °C, 355 K).
L
Cook time is based on principles of
diffusion
• 𝑇𝑓𝑜𝑜𝑑 = set temp. = 180 °F
• 𝑇𝑒𝑥𝑡 = oven temp. = 400 °F
• 𝑇0 = room temp. = 75 °F
• 𝐷ℎ𝑒𝑎𝑡 ≈ 𝐷𝑤𝑎𝑡𝑒𝑟 = 1.4 ∗
About 11 minutes
2
𝑐𝑚
10−3
𝑠
• 𝐿 = radius of cake = 3 𝑐𝑚
(diffusivity of heat)
Baking
• Expansion
• Setting
• Browning – 250 °F, 121 °C, 394 K
Maillard Browning
• Maillard reaction – reaction between an
amino acid and a sugar
• Sugar + Protein + Heat → Components + Volatile
Compounds (brown pigment and new aromas)
• Only occurs in dry conditions (cake needs to dry out
a little on the edges)
http://www.kingarthurflour.com/blog/2010/03/07/warning-everything-but-the-kitchen-sink-carrot-cake-is-not-for-purists/
What kind of aromas?
• Savory (break proteins into peptides and
amino acids)
• Floral (oxazoles)
• Onions and meatiness (sulfur compounds)
• Green vegetables (pyridines, pyrazines)
• Chocolate (pyrazines)
• Potato, earthy (pyrazines)
• Also, carmelization flavors
From On Food and Cooking by H. McGee
Caramel glaze for cake starts with sugar
http://idesigniphone.com/sugar-cubes
Adding heat provides activation energy
for the caramelization reaction
Sugar + Heat → Components + Volatile
Compounds + Brown pigment
http://butterbadge.wordpress.com/
What kind of flavors are formed?
•
•
•
•
•
•
•
•
Sweet (break complex sugars into simple sugars)
Sour (acetic acid)
Bitter (complex molecules)
Fruity (esters)
Sherry-like (acetaldehyde)
Butter (diacetyl)
Caramel (maltol)
Nutty (furans)
From On Food and Cooking by H. McGee
Adding cream provides proteins so the
Maillard reaction can occur
Caramel glaze
contains all of the
aromas from
caramelization and
Maillard browning
http://www.bettycrocker.com/tips/tipslibrary/cooking-tips/stout-caramel-sauce
11 ingredients + chemistry → many
complex aromas and flavors
http://smittenkitchen.com/blog/2007/12/caramel-cake/