Why Do Eggs Need To Be at Room Temperature for Baking?

For a lot of us who've been casually baking for a long time, who learned at the hands of our mother or grandmother (or in my case, great grandmother), it's all too easy to sometimes overlook the fact that baking a cake relies on chemistry, just as much as it does muscle memory. Accordingly, producing the best possible result (i.e. the most tender cake) often relies on understanding — and acknowledging — certain chemical principles.

Much of the time, a recipe will provide certain cues and reminders of the places where these details of ingredient chemistry really matter, like when a recipe calls for a select number of "large eggs, at room temperature." Using eggs that are at room temp is a fairly common instruction in baking recipes, and I'd imagine it's also a commonly ignored instruction in many kitchens. I mean, let's be honest, if an instruction requires added time and/or effort to a project, and we don't really see what difference it makes whether or not we adhere to it, plenty of us are going to proceed as if it weren't even there.

So really, why is this instruction there?

Why Should You Bake With Room Temperature Eggs?

When you see a note about temperature tacked onto a listing in a recipe's ingredient list, understand that this is an indicator that temperature does actually matter to the ultimate success of your baked good(s). In fact, you can consider this as important as accurately following the measurements provided. You can consider baking an art, rooted in science.

Most of us immediately understand why butter needs to be at room temperature if you intend to cream it with sugar (and remember, you tend to see some iteration of the phrase "beat until fluffy," in tandem with this room temperature ingredient — that's telling/important). The most obvious reason is that butter that's at room temperature, or "softened," is much easier to combine with the sugar, and then the other ingredients; same goes for eggs.

Eggs that are at room temperature are more easily and quickly dispersed and blended with the other ingredients to form a stable emulsion — you'll recognize that "stable emulsion" as a smooth, cohesive batter.

In some cases, using chilled eggs can effectively work against forming a well-emulsified batter. Mixing eggs straight from the fridge into room temperature butter causes a temperature disparity that can shock the fat, leading it to seize and curdle. This will ultimately not prove beneficial for the texture of your cake.

Now, the less obvious, but entirely essential, role that temperature plays when it comes to these ingredients involves air pockets. See, when you beat an egg, the proteins present in the egg are prone to capture pockets or bubbles of air — and eggs are able to do this most effectively when they're at room temperature. These contained air pockets expand during baking and result in a baked good that is airy, tender, and fluffy. Think about it, this is why you whisk eggs well before scrambling them in a pan or making an omelet...you want fluffiness!

Do Eggs Always Need to Be at Room Temperature for Baking?

In short, no — eggs do not have to be at room temperature for every type of baking recipe. In general, it's always a good idea for cakes and other baked goods that you want to have a fluffy texture. Otherwise, you can rely on your recipe to let you know when their being room temperature is essential.

For example, with making most drop cookies, I never really worry about having room temperature eggs to work with, because fluffiness isn't a texture I'm going for — it's more important to me that my chocolate chip cookie is chewy versus airy.

What About Other Chilled Ingredients In the Recipe?

There are a few other ingredients you'll commonly see called for being brought to room temperature before adding them into a baking recipe: Butter, cream cheese, and "liquid" dairy products such as milk, buttermilk, yogurt, and sour cream. For all of these, the rationale is just about the same as for eggs.

Room temperature ingredients are more easily incorporated with one another. And all of these dairy items have proteins that will do the best job of locking in minuscule air bubbles if they are at room temperature.

With that said, let this be the day that you begin taking the recipe phrase "at room temperature" seriously.

Read More Baking Tips:

• Types of Baking Fats and the Benefits of Each
• Glass vs. Metal: Which Pans are Better for Baking?
• To Sift or Not to Sift: Is It a Waste of Time?