Cookie Cooling: Thermodynamics Approach
I heard somebody was planning on making cookies in the next six weeks. Here are my thoughts. :-)
To start with, you need to know that I like my cookies crisp. My ideal chocolated item is oatmeal chocolate chip--more oats than chocolate-- crisp around the edges and jaw-working chewy inside. It's moist, but not damp. Macadamia nuts are good in those. I like biscotti with no dunking beverage, and use zweiback for cheesecake crust crumbs. Brownies for Just-Me consists of enough batter to bind the pecans, but only barely. Start those with butter and unsweetened chocolate. :-D
Moist chewy cookies get farmed out to Mathematicians.
As I see it, there are several approaches.
1. Cool on the pan until pan and cookies are cold.
2. Cool on the pan for a couple minutes, then remove to another surface.
3. Immediately remove from pan onto another surface.
Approach 1 works for bar cookies, like brownies. It would unnecessarily tie up a sheet pan otherwise, and the likelihood of sticking seems rather great. Mayhap also overcook the cookies.
Approach 3 works for super-delicate things, cookies that are going to harden up Quick! like fortune cookies and the pretty oat lacy cookies (oats in a fine brittle mesh).
I tend to favor Approach 2. What surface to use?
A. Wire rack
B. Mesh rack
C. Another cookie sheet
D. Paper towel
E. Paper bag
F. Clean kitchen towel
G. Aluminum foil
H. Serving platter
I. Your hand
Keeping in mind that a cookie, as it comes out of the oven, is a dynamic system of steam, gluten, hot sugar, and molten fat. The goal of cooling a cookie is to release enough heat such that the gluten matrix can set up firmly. Leaving it on the pan continues to cook the bottom, while minimizing top cooking. Sometimes cookies look underdone because the inside is so melty that the gluten matrix is having trouble setting up. Leaving it on the tray for a couple minutes will give it that bit of extra heat to the core, while the outside starts cooling. Cookies that fold when you take a spatula to them? No. Just no.
An open-to-the-air surface, like the wire and mesh racks, will allow water vapor to evaporate as the cookie cools. Solid surfaces would trap this moisture underneath the cookie, softening the bottom. It seems to me that the more fat is in a cookie, the longer it would take to cool, due to the difference in thermal conductivity between water and oil. Thinner cookies cool much faster--surface to volume ratio is key.
Transferring to another cookie sheet doesn't make sense to me, but I do cool scones upside-down on their own tray. The craggy tops don't sit flat, so the scones don't have their heat trapped.
Using a paper towel or paper bag would depend on what kind of surface is underneath. These surfaces would absorb fat from the cookie, but I'm not sure that enough steam would be released for the bottom to be dry. I'd also be concerned about the processing chemicals and other residues in/on the paper. I re-use my paper bags for groceries many times, so wouldn't want to use them for cooking. My mother makes baked meringue on brown paper. It's classic.
A paper towel on a cookie rack might split the difference between absorption and steam loss?
Dish towel-cooling is the method I grew up with. The clean towels are placed on a tile counter, to maximize item count. Also this saves washing the cooling rack or getting crumbs all over everywhere. One just must remember to dislodge the warmish cookies to peel the towel off before the little terry loops embed irretriveably into the cookie.
Aluminum foil, like a cold pan, is a moisture-impenetrable surface. Hello moist bottom. Barelyproper suggests a light crumple-unfold to get height unevenness into the foil, which will enhance air circulation. (Thanks!)
Additionally! there is a good use for foil in the garage. Take clean foil and lay it on a cleanish-looking cement garage floor. Take hot soup and transfer into gallon-size ziploc baggies. Carry soup into garage and lay it out flat on the foil. Presuming cold cement and periodic agitation, the aluminum will conduct the heat out of the soup in a decently fast manner, such that the resulting cold soup goes into the fridge easily. I did this for VoR's Spanish Meats and Huge Beans soup a couple years ago, during the cold season. Twenty minutes, perhaps, for two gallon-bags.
Straight onto the serving platter results in soft cookies. Maybe that's okay if the expected shelf life is half an hour total. There's no circulation anywhere, and the heat is trapped.
From the cookie sheet straight to your hand is fine, so long as you don't burn your mouth. Remember that hot fat/molten sugar thing? That 50+degree temperature difference between cookie and self? Be careful there.
In summary: how you cool your cookie depends entirely on what kind of cookie it is and how you want your end product to be.
To start with, you need to know that I like my cookies crisp. My ideal chocolated item is oatmeal chocolate chip--more oats than chocolate-- crisp around the edges and jaw-working chewy inside. It's moist, but not damp. Macadamia nuts are good in those. I like biscotti with no dunking beverage, and use zweiback for cheesecake crust crumbs. Brownies for Just-Me consists of enough batter to bind the pecans, but only barely. Start those with butter and unsweetened chocolate. :-D
Moist chewy cookies get farmed out to Mathematicians.
As I see it, there are several approaches.
1. Cool on the pan until pan and cookies are cold.
2. Cool on the pan for a couple minutes, then remove to another surface.
3. Immediately remove from pan onto another surface.
Approach 1 works for bar cookies, like brownies. It would unnecessarily tie up a sheet pan otherwise, and the likelihood of sticking seems rather great. Mayhap also overcook the cookies.
Approach 3 works for super-delicate things, cookies that are going to harden up Quick! like fortune cookies and the pretty oat lacy cookies (oats in a fine brittle mesh).
I tend to favor Approach 2. What surface to use?
A. Wire rack
B. Mesh rack
C. Another cookie sheet
D. Paper towel
E. Paper bag
F. Clean kitchen towel
G. Aluminum foil
H. Serving platter
I. Your hand
Keeping in mind that a cookie, as it comes out of the oven, is a dynamic system of steam, gluten, hot sugar, and molten fat. The goal of cooling a cookie is to release enough heat such that the gluten matrix can set up firmly. Leaving it on the pan continues to cook the bottom, while minimizing top cooking. Sometimes cookies look underdone because the inside is so melty that the gluten matrix is having trouble setting up. Leaving it on the tray for a couple minutes will give it that bit of extra heat to the core, while the outside starts cooling. Cookies that fold when you take a spatula to them? No. Just no.
An open-to-the-air surface, like the wire and mesh racks, will allow water vapor to evaporate as the cookie cools. Solid surfaces would trap this moisture underneath the cookie, softening the bottom. It seems to me that the more fat is in a cookie, the longer it would take to cool, due to the difference in thermal conductivity between water and oil. Thinner cookies cool much faster--surface to volume ratio is key.
Transferring to another cookie sheet doesn't make sense to me, but I do cool scones upside-down on their own tray. The craggy tops don't sit flat, so the scones don't have their heat trapped.
Using a paper towel or paper bag would depend on what kind of surface is underneath. These surfaces would absorb fat from the cookie, but I'm not sure that enough steam would be released for the bottom to be dry. I'd also be concerned about the processing chemicals and other residues in/on the paper. I re-use my paper bags for groceries many times, so wouldn't want to use them for cooking. My mother makes baked meringue on brown paper. It's classic.
A paper towel on a cookie rack might split the difference between absorption and steam loss?
Dish towel-cooling is the method I grew up with. The clean towels are placed on a tile counter, to maximize item count. Also this saves washing the cooling rack or getting crumbs all over everywhere. One just must remember to dislodge the warmish cookies to peel the towel off before the little terry loops embed irretriveably into the cookie.
Aluminum foil, like a cold pan, is a moisture-impenetrable surface. Hello moist bottom. Barelyproper suggests a light crumple-unfold to get height unevenness into the foil, which will enhance air circulation. (Thanks!)
Additionally! there is a good use for foil in the garage. Take clean foil and lay it on a cleanish-looking cement garage floor. Take hot soup and transfer into gallon-size ziploc baggies. Carry soup into garage and lay it out flat on the foil. Presuming cold cement and periodic agitation, the aluminum will conduct the heat out of the soup in a decently fast manner, such that the resulting cold soup goes into the fridge easily. I did this for VoR's Spanish Meats and Huge Beans soup a couple years ago, during the cold season. Twenty minutes, perhaps, for two gallon-bags.
Straight onto the serving platter results in soft cookies. Maybe that's okay if the expected shelf life is half an hour total. There's no circulation anywhere, and the heat is trapped.
From the cookie sheet straight to your hand is fine, so long as you don't burn your mouth. Remember that hot fat/molten sugar thing? That 50+degree temperature difference between cookie and self? Be careful there.
In summary: how you cool your cookie depends entirely on what kind of cookie it is and how you want your end product to be.