Day 4 of #RCIAdvent is brought to you by the Cookie Monster! Baking the ideal cookie seems to be a matter of preference - do you like yours gooey? Chewy? Crispy? Whatever your taste, we’re here to help engineer the perfect chocolate chip cookie for you this holiday season.
You might remember from our Great Pandemic Bake Off event, when it comes to baking, every ingredient serves a specific purpose. The more you understand their roles, the more you can tweak and experiment with a recipe to craft the perfect cookie for you.
Butter
Butter is typically about 80-83% fat, 15% water and 3-5% milk protein. Gluten – a tough, stretchy network of interconnected proteins developed when flour is mixed with water – can’t form in fat. So the more butter you use in your recipe, the less gluten that forms and the more tender (and spread out) your cookies will be.
The temperature of your butter also plays a role in the cookie’s texture. It changes the air pockets left behind as the water in the butter converts into gas. Creaming cool butter and sugar until it’s light and fluffy gives larger pockets of air, mechanically leavening the cookies and giving them a fluffier, cakier rise.
Melting butter before combining it with sugar and eggs leads to squatter, denser cookies. It gives a more chewy and crisp texture, because the water is released from the fat, allowing more gluten to develop before the dough goes into the oven.
Note dough containing warm butter tends to spread before the eggs and leavener are able to set the cookie.
Sugar
The type of sugar you use really impacts the finished product.
Granulated sugar is crystallized sucrose, a disaccharide consisting of a fructose and glucose molecule linked together. It is mildly hygroscopic (it likes to retain moisture), and relatively neutral in pH.
Brown sugar is predominantly crystallized sucrose, but it also contains glucose and fructose, which are far more hygroscopic than sucrose. Bonus: these sugars churn out rich, complex tastes from the Maillard reaction. Store-bought brown sugar contains some molasses mixed in, giving it a rich toffee flavour and a slightly acidic pH.
The acid in brown sugar reacts with the chemical leavener (typically baking soda or baking powder), causing the cookies to rise in the oven. This limits their spread and leads to a cakier texture. Granulated sugar cookies are crispier and spread out more, since there's no acid to activate the leavener and contribute to the rise and they more readily give up moisture.
A mixture of sugars typically works out best, with brown sugar adding to the rise, but granulated sugar allowing the cookies to spread before they become too cakey.
Eggs
Eggs are the main source of water in a cookie dough recipe, hydrating the flour, facilitating the development of gluten and helping to dissolve the sugar. Egg whites trap air bubbles, making cookies lighter and taller. Egg yolks contain more fat and when cooked, the yolks form a tender protein coagulum that can keep cookies tender and fudge-like. A high proportion of egg yolk leads to a more brownie-like texture in a finished cookie.
Flour
Flour gives your cookies structure. Proteins in the flour mix with water from the eggs and butter to make gluten. Gluten formation in cookies is usually fairly minimal, compared with, say, bread. Higher-protein bread flour makes for a chewier cookie; lower-protein cake flour gives a tender, cake-like cookie.
The ratio of flour to butter also impacts the texture of your cookies. A small amount of flour compared to butter results in cookies that spread out into a wafer-like lace cookie. Extra flour results in cookies that barely spread as they bake, with centers that stay dense and dough-like, even after being almost fully cooked.
Leavening Agents
Leavening is the introduction of air to the internal structure of baked goods and it can come in many forms. We mentioned creaming butter introduces mechanical leavening, and the capture of expanding gases by egg proteins also plays a role. But in cookies, we rely on chemical leavening agents, typically baking soda and baking powder.
Baking soda is pure sodium bicarbonate, an alkaline powder. When dissolved in liquid and combined with an acid, it reacts quickly, breaking down into sodium, water and carbon dioxide. Remember brown sugar can provide the acid that reacts with baking soda.
Baking powder is baking soda with powdered acids added. It’s inert when dry but once you add a liquid, the powdered acid and base dissolve and react with each other, creating bubbles of carbon dioxide without the need for an external source of acid. Many baking powders nowadays are double acting – they contain two different powdered acids. One reacts immediately upon mixing with water, while the other only reacts after it's heated, giving cakes and cookies a boost early in the baking phase.
Baking powder generally produces cakier cookies that rise higher during baking, producing smoother, shinier tops. Baking soda yields cookies that are craggier and denser in texture. Dealer’s choice.
Chocolate
The size, shape, and cacao percentage of your chocolate will determine how chocolaty your final cookie will be. Semisweet or bittersweet chocolate ranges between 40-70% cacao. The lower the cacao percentage, the sweeter and less bitter the chocolate.
Chocolate chips retain their shape during baking, producing regular cookies, with small, melty pockets of chocolate. Bonus: they’re convenient. Chocolate discs and chunks cause some degree of layering in the dough, creating a flakier cookie with larger sections of molten chocolate. Hand chopped chocolate produces the most contrast. Small bits of chocolate are dispersed throughout the cookie dough, disrupting its texture and giving a deeper chocolate flavour, while larger chunks still melt into large gooey pockets.
Salt
Salt balances the flavour of caramelized sugars and reduces the bitterness of dark chocolate. Kosher salt flakes are larger than table salt, so if you’re using fine-grained salt it’s probably best to cut the measure in half.
Rest. Your. Dough.
Admittedly, no one wants to wait for cookie dough to rest, but resting your dough gives your cookies deeper flavour and even browning and texture. During the browning process, large protein and starch structures are broken down into smaller parts and rearranged. Resting overnight gives this deconstruction phase a jumpstart, resulting in cookies with deeper brown sugar and caramel flavours. Yum.
So there you have it. In eight easily manipulated variables you can bend just about any chocolate chip cookie recipe to your will! But, like the Cookie Monster, we’re not picky...
If you’re really into the science of baking the perfect chocolate chip cookie, may we suggest visiting Serious Eats for a very in depth analysis of just about every variable that can impact the final result of your cookie bake?!