Once a year, I get an itch to go through my recipes to see if I can make them better. The recipes can be something newly created or an old standby, it doesn’t really matter. It’s a chance to apply new things I’ve picked up and learned and hopefully make my products better than they were before. Not long ago the time came for me to play around with my chocolate chip cookies and it got me to thinking about a blog post.
Here on DFK we’ve dabbled a little into the science behind some ingredients and a few recipes, but we haven’t yet tackled the complex inner-workings of a baked good. Well, pastry fiends it’s time to do just that, and what better baked good to use as a test subject than my most favorite cookie in all the land, the chocolate chip? More than just a fantastic cookie (and an indisputably American creation – take that, world), chocolate chip cookies are a great example of basic food science. As a chef instructor it was one of the first things I demonstrated to a new class since it touches on so many basic concepts.
To be honest, there’s so much you can test and play with in even just a simple chocolate chip cookie recipe that it couldn’t all fit in one post. Well, it could, but it would be one long-ass post. So let’s consider this an intro into the science of the chocolate chip cookie where we focus on the role of ingredients and how a recipe structure can change results. We can all look forward to more DFK tests down the road.
test 1
All of my testing was based on the major components of a cookie: flour, butter, sugar, eggs, leavening. For test 1 I used the same exact recipe and with each batch I changed a single ingredient by either variety (all purpose flour v. cake flour) or method of application (room temperature butter v. melted butter). Oh and just to set the scene, each recipe was individually scaled to the tenth of a gram and received equal mixing times, resting times, baking setup (double sheet pan with a non-stick baking mat* – just like we make them at work), baking time and oven rotation. Every possible variable that could be controlled was monitored. 10-4 over and out.
*There are some cooks out there who insist on baking cookies on parchment paper as it doesn’t insulate much heat and helps the cookie brown on the bottom. I don’t know about you, but I’ve never had a problem with my cookies browning on the bottom during baking, either at home or at work. My problem is just the opposite – brown, crispy bottoms from too much heat before the rest of the cookie has even baked! I use a silicone baking mat and two stacked sheet pans specifically because it will insulate from the heat of the oven and allow the cookies to bake more evenly, albeit for a little more time than when baked on parchment.
If you look at the results from test 1 and don’t notice much difference, you’re not alone. I don’t either. With just a few exceptions, you can see that changing out one variety of ingredient for another (like brown sugar v. granulated sugar) doesn’t have a lot of physical effect. Yes, there are some changes in flavor and texture (you’ll have to take my word for it) but even so, you could hand me a cookie made with pastry flour and one made with all-purpose flour and I could only tell you that both are delicious.
If you’ve ever checked out one of the many other blogs out there on the science of chocolate chip cookies, you might be scratching your head at this point. Why don’t these look like the wildly different results that other blogs showcase!? I thought we were supposed to see a crazy array of cookies with different sizes, shapes and colors! Now I’m not saying other blogs are wrong and I’m right, or I’m wrong and they’re right but I’ve baked a whole sh*tload of cookies in my day and I trust my method. The results I got don’t really surprise me. A chocolate chip cookie is a very solid recipe; it can withstand a lot of abuse in method and ingredient choice and still yield an acceptable and largely similar result. If we had made the same type of tests on an angel food cake you’d absolutely see major changes in the final product because a angel food cake is a more delicate recipe. So what gives?
My hypothesis, and the start of my second round of testing, is that maybe in other blog posts the ratio of the ingredients in the cookie recipe was altered as well, not just the ingredient’s type. This is especially true if archaic cups and tablespoons are being used to measure.
Differences in ingredient weights combined with other small variances in method, like baking one batch of cookies on parchment and another on a baking mat (which incidentally will effect spread, rise, color and baking time), or one set chilled and one slightly warmer, would have big changes in the final cookie.
test 2
To really understand the affect of each ingredient in the recipe of a cookie, we need to start to play with ratio. My second set of testing (now back at my home kitchen) isolated each of the major components of the cookie and adjusted the quantity up and down with a control to compare to. I increased and decreased the amount of each ingredient by 40% (by weight). 40% is a huge difference in a recipe and it’s rare you would make such a dramatic adjustment, but I wanted to be sure that the impact of more or less of the ingredient would be obvious.
Whelp, that’s obvious alright. Looking at the results of this test in comparison to test numero uno, you can see how powerful the ratio in a recipe is. I mean, duh. That’s why I emphasize using a gram scale to ensure measurements are accurate!
Ok, so we’ve done the tests, now let’s analyze the results. Below I’ve put together some facts on each ingredient category and how they correlate to your cookie. Don’t forget that the general science we’re talking about today applies to all baked goods!
flour
in your recipe
Above all flour will provide structure to your cookie. Protein in the flour forms gluten and that network will give the cookie stability before and after baking, trap gasses during baking to help the product rise and expand, and have a big impact in creating the final crumb (texture).
Both the protein and starch in the flour will absorb water and fat, which will help hom*ogenization (ingredient mixing) and emulsification (fat and water binding). The absorbed water will convert to steam during baking and then in turn be contained by the gluten network, expanding it to help product rise. Remaining water left in the cookie will contribute to moistness.
Lastly, flour will add color and flavor to your cookie. Proteins and sugars in the flour will help Maillard browning during baking to create complex flavor combinations and help give your cookie that golden hue you know and love.
Altering the flour content of the cookie yields the biggest physical difference. With low flour content, the relative moisture content of the dough is much higher, creating more spread, more browning and a much crispier cookie. With high flour content, the dry dough doesn’t spread much at all and has a dry, cake-like texture.
more v. less
More flour, regardless of what type, is going to create a cookie with less spread and a more cake-like texture and flavor. Because of all the extra structure, the cookie will rise higher too.
Less flour in your recipe will increase the relative ratio of water and fat and the cookie will have more spread and a denser, chewier texture. Even though flour aids in browning, the darker color of the low flour cookie is do to an increase in sugar and butter by ratio in the total recipe weight, both of which has more overall effect on caramelization and color than flour. Not only that, but more spread means more surface area exposed to heat, so the cookie bakes faster.
flour variations
The higher the protein content of the flour you use (bread flour and all-purpose flour), the chewier and denser the cookie will be while lower protein flour (pastry and cake flour) will produce a more cake-like crumb. In truth, altering the flour in your cookie recipe won’t have as much effect as you might think, since you’re really only mixing the dough until it is combined, and not really giving an opportunity for gluten to form. If you wanted to make a truly dense cookie, you could use high protein flour and intentionally overmix the dough to develop some gluten.
eggs
in your recipe
Eggs contribute so much to a cookie. Egg white proteins help to develop structure, much like flour. During baking, the egg white proteins coagulate and form a permanent mesh (working together with gluten) that supports air pockets created by expanding gases.
The water in egg whites contributes to almost all of the water in your dough, adding moistness, assisting in leavening during baking as it turns to steam, interacting with flour protein and starch to create gluten and starch gelatinization and combining with sugar to form a syrup that prevents too much structure from developing. Whew!
Egg yolks will add flavorful fat to the cookie and natural emulsifiers – lecithin – will help all fat and water in the dough bind together harmoniously. Carotenoids in the yolks will provide some color to the cookie as well.
Physically there doesn’t seem to be a lot of difference in spread or color in the tests. From a taste test perspective, the higher egg cookie had more rise and a slightly cakier texture thanks to the additional egg white protein in the dough.
more v. less
More egg in a cookie is more water beyond all else. More water is going to increase spread, reduce the rise of the cookie and create a more dense and chewy texture. Less egg creates a more cake-like texture with less color and a drier texture.
egg variations
egg whites
A cookie made with all egg whites will have more structure resulting in less spread and more rise. Because egg whites lack carotenoids and fat, an all egg white cookie will be paler in color and have less flavor. Egg white proteins create a lot of the eggy flavor of eggs, so using all egg white in your cookie can add that flavor effect as well.
egg yolks
Using all egg yolks in a cookie will add flavor and color to your final product and create more spread and less rise. Overall a cookie made with all egg yolks will be richer in flavor and mouthfeel, similar to adding extra butter.
sugar
in your recipe
Most obviously sugar will add sweetness to your cookie. This is a pretty “no duh” point, but it’s important to mention that not all sugar packs the same sweetness punch. It’s pretty unlikely you’ll add a specialty sugar to your cookie with a drastic difference in sweetening power (that’s how the sweetness of sugar is evaluated) but it’s still good to keep in mind.
Just as importantly as adding sweetness, since sugar is hygroscopic (water attracting), it will bind to and retain water in the finished cookie. This will make the cookie more moist and also extend the cookie’s shelf life by reducing bacteria-developing active water and slowing down staling.
Once sugar is incorporated with the water in the recipe – from the eggs and butter – some of it will dissolve and form a syrup. That syrup will slow gluten formation and starch gelatinization, inhibiting the structure formed by flour and eggs so that the cookie doesn’t rise too much.
Sugar is crucial in browning baked goods, and cookies are no exception. Through Maillard browning and caramelizing during baking, sugar adds to the depth of flavor and color of a finished cookie.
I really like this shot. You can see the gradual darkening and spread of the cookie as more and more sugar is added. And of course the high sugar cookie is sweeter. The low sugar cookie being less sweet really emphasizes the final texture and pronounces the dryness in a (in my opinion) negative way.
more v. less
More sugar will make your cookie sweeter, give it more spread, create a darker final color and more caramel notes in the flavor. More sugar will also create a more moist cookie with a longer shelf life. Less sugar will have all of the opposite effects, as you can see in the wonderful picture above. Science!
sugar variations
granulated sugar
The granule size of granulated sugar will have a median ability to dissolve into the water of a cookie dough, creating a syrup without all of the sugar dissolving. This combination of syrup and undissolved sugar will create a cookie with a good balance of crispiness and chewiness. Granulated sugar lacks acid, so it won’t react with baking soda in a cookie recipe to promote rise.
brown sugar
The addition of water and malted flavor will give cookies with brown sugar a deeper flavor and a chewier texture. The caramel coloring in brown sugar can create a slight color difference after baking. Brown sugar contains a good amount of acid relative to other sugar varieties, which can increase the ability of baking powder and soda to leaven the cookie.
turbinado sugar
Turbinado sugar, or sugar in the raw, is a much larger grain size than standard granulated sugar and so it will not dissolve as easily into the recipe’s water. Cookies with sugar in the raw will have a crispier, crunchier texture. Since Turbinado sugar is treated with malted syrup it will have some of the characteristics of brown sugar in terms of flavor and color.
powdered sugar
Powdered sugar will dissolve most easily of all sugar varieties which will eliminate most sugar crunch in the cookie’s texture as a result of the syrup formed. This is especially true when you combine powdered sugar with melted butter which can also create a smooth, shiny surface to the baked cookie. Keep in mind that powdered sugar contains starch, and that can prevent extra spread in your cookie.
butter
in your recipe
Adding butter to your cookie dough is really adding two things: fat and water. Don’t forget that even high quality butter will add as much as 18% water by weight. We’ll keep this in mind as we talk about butter’s impact on a cookie.
Tackling fat first, butterfat is going to add a pleasing mouthfeel and texture to your cookie as well as lots of great flavor. Butterfat coats proteins in your recipe (both flour and egg proteins) and prevents them from binding together and that means butter prevents structure building. There are small amounts of carotenoids, sugars and proteins in butter as well, all of which will add to the browning of the cookie during baking.
Water in the butter will aid in leavening the cookie during baking and any remaining water after baking will contribute to moistness in the cookie’s texture.
The higher butter cookie has slightly more spread than the low butter and control. The biggest difference is in the flavor and mouthfeel of the cookie. The high butter cookie has great flavor but at 40% increase it is greasy to the touch and in mouthfeel.
more v. less
More butter will create more spread in your cookie and a richer flavor with a denser texture. Careful though, because too much butter can create a greasy feel in the finished cookie.
Less butter will reduce spread and will overall result in a less flavorful and lighter finished product.
butter variations
melted butter
Melting your butter before adding it to your dough will give the cookie more spread, a denser texture and a shinier crust. The liquid fat will coat protein and starch more easily and more thoroughly prevent them from binding and developing structure. Water separated from the butter as it melts will contribute to dissolving sugar in the recipe to create a syrup which will also inhibit structure and create a smooth and somewhat shiny surface on the cookie when it’s baked.
clarified butter
When you add clarified butter to your cookie, you’re adding pure butterfat without some of the great things that make butter, butter. Things like water, milk solids and lactose (sugar). Because it lacks these things, clarified butter will reduce the moistness of the finished cookie, the rise and some of the ability of the cookie to brown during baking.
browned butter
Browned butter has had its water removed too, and then the milk solids are caramelized giving the butter the obvious color but also a rich, nutty flavor. Although you won’t be adding water to your cookie dough, you will depth of flavor thanks to the caramelized sugars and proteins.
leavening
in your recipe
The leaveners in your cookie dough – baking powder and soda – are going to, well, leaven your cookie. Other than water, the carbon dioxide created by both baking powder and soda will be the gas that expands during baking, creating air pockets supported by protein networks and resulting in the crumb, or final texture, of your cookie.
Of all the testing, adjusting the leavening had the littlest effect. Low leavening means the cookie tends to bake out instead of up, resulting in more spread. You can see evidence of that in the photo above, and by adding leavening you create a light, more cake-like texture.
more v. less
More or less leavener in your cookie dough, whether it’s baking soda or baking powder, will have little overall effect on your cookie. I know this sounds a little nuts, but the proof is in the cookie. In both test 1, where one leavener or the other was exclusively used and test 2, where the combined total of the recipe was greatly increased and decreased, there’s not much difference in result.
This is largely do to the fact that a chocolate chip cookie doesn’t rely on a lot of chemical leavening in the first place, and what rise does occur is largely thanks to the recipe’s water. That being said, more baking powder will have a slight increase in rise with the baked cookie and will prevent too much spread. Less leavening will create a slightly more dense cookie with a little more outward spread. One think to take note of is the strong flavor of baking soda. At large quantities your baked good can quickly take on an alkaline, chemical flavor from baking soda.
conclusions
To be honest, we’ve still only scratched the surface of the science of the chocolate chip cookie, but there’s still a lot to take away from our tests. Overall, the ratio of a recipe will have a greater effect on the finished product than ingredient variation. All manipulation of the cookie, whether ingredient or quantity, will have some universal impact: the cookie will become more chewy or more cake-like, have more spread or less, brown more or less (which could read as more or less complex flavor).
We covered a lot of ground today! When next we visit the science of the cookie we’ll get into altering multiple ingredients within the recipe in order to create specific desired results AND start to mess with method and chocolate. For now, digest the info above (get it???) and go forth into the world more prepared to make the cookie of your dreams.
Cheers – Chef Scott
