Does Egg Size Really Matter for Baking? | America's Test Kitchen (2024)

We know that baking is equal parts science and art; exact measurements and precise oven times can make or break the perfect bake.

The reason the size of your eggs can affect the outcome of your baking is mostly down to water content. An egg yolk is 50% water, and an egg white is 90% water. This means that using a larger egg than a recipe calls for can throw off the moisture balance—and if your recipe calls for multiple eggs, the problem is compounded.

This issue could definitely cause a problem in cookies, for example. Too large an egg can result in a wetter-than-intended dough, which could make your cookies spread more and be flatter. Using too small an egg could pose problems in the opposite direction: stunted, humped cookies.

Using eggs that are the wrong size could also impact cakes, especially those in which whipped egg whites are used, such as genoise or angel food cake. If your eggs are too small, you’ll likely not get the lift you’re after.

As you might expect, the differences in size between jumbo, large, and medium eggs aren’t easily quantifiable, and the idea of incorporating 3⅔ eggs into your dough can be perplexing (though we can tell you how to measure half of an egg here).

But there is a simple workaround: Weigh your eggs.

We recommend that you pool the number of eggs that you need together and lightly beat them to combine the yolks and whites, and then weigh out the total amount that you’ll need from this mixture. This will ensure you that you have the right ratio of water, yolk and white for your bake.

You can refer to the table below to ascertain the weight of egg you’ll need for the recipe you’re using:

Egg Sizes and Weight

If you have eggs of different sizes and your recipe calls for separating your eggs, you might need to pool your whites, pool your yolks, and then weigh each separately to ensure accuracy for each.