How do variations in the proportions of ingredients affect a final product?
The Thin focused on deviations from Ruth Wakefield’s TOLL HOUSE® Chocolate Chip Cookie recipe to produce a flat, crisp cookie that spreads before it sets. However, there are other variations of the chocolate chip cookie. As I have mentioned several times, there are three basic styles of the chocolate chip cookie: the thin, the puffy, and the chewy. All these styles are defined by its texture or appearance.
The Puffy suggests the baked cookie is airy. The texture should be light and soft – like a cake. What is needed to obtain such a texture? Consider…the fat.
From The Thin, I quote myself, “nothing affects the texture of a cookie more than the melting characteristics of its fat.”
Wakefield’s original ingredients call for butter. As mentioned in The Thin, butter has a low and sharp melting point. That means that the range of temperature at which the solid butter melts into a liquid phase is relatively narrow and is low – not much warmer than room temperature. With such a low temperature, the butter would melt and promote spreading of the batter.
However, for a puffy cookie, the height of the cookie must remain tall. A taller cookie decreases its surface-to-mass ratio.
Why would the surface-to-mass ratio affect cooking?
Remember that heat from an oven is multidirectional. This is possible due to three distinct types of energy acted upon the food. Conduction from the direct contact of the metal of the cookie sheet heats the bottom of the cookies. Radiant heat from elements or coils sends direct energy to the food through heat. Convection is the energy of the air inside the oven circulating all around the food.
Notice: Conduction is the direct contact with metal, radiation is the energy transferred from the heating element as heat, and convection is the circulation of heated air in the oven.
With this quick background in the multidirectional heat of ovens, the more surface there is on the cookie, the more energy is acted upon the food ruins the puff factor of a puffy cookie.
Egg whites contain a lot of protein. When the proteins in egg whites are cooked, they coagulate to form a network that can “catch” pockets of steam to provide. Yes, steam provides some of the “lift” needed for that airy texture. The other pockets are full of air from the carbon dioxide formed from mixing an acid and base.
Subscribe to:
Post Comments (Atom)
I've been waiting for this, and it oes not disappoint. The number of angles from which you're prepared to discuss the working mechanisms--from chemistry to thermodynamics--is amazing.
ReplyDeleteI'm not sure you're in total control of your explanation by the end, though. Each of the last four or five paragraphs made sense to me by themselves, but how they fit together and add up to a fluffly cookie eluded me somewhat. The answer is eggs instead of butter? But then what fat is used?
I love your posts so much, Chris! :D
ReplyDeleteI learn something new or refine old knowledge every time
Aw. Thanks Eunjin and Mr. Sutherland. Always nice to hear from other people.
ReplyDeleteI guess I rushed the end a bit too quickly - as you can see by the time stamp, always coming in a few seconds before the bell. It's an important aspect of writing, that acutally isn't writing at all: time management.
And then after that, I don't even re-read what I wrote. Bah!
I didn't mention this. Butter should be replaced with a butter-flavored shortening. Because of its refinement and stabalized molecular structure, it melts at a higher temperature.
Using more egg whites in puffy cookies yields a more airy texture. Sorry for the confusion. You can always ask in person for better explanations =]