Natural ingredients such as eggs vary widely in size, which can occasionally be a problem for cooks and bakers. Recipes are typically based on a standard "large" egg, and if yours are notably larger or smaller -- especially when baking -- it can skew your results.
The Size Difference
Egg sizes are based on weight, because it's a quick and easy test. Large eggs average 24 ounces, or 1 1/2 pounds, per dozen. Extra-large eggs weigh 27 ounces per dozen, or an extra quarter-ounce per egg. You'll see variation between individual eggs, but the average is pretty reliable. For home bakers, an egg's volume is more important, but -- since the volume of an egg determines its weight -- the difference in size works out to be much the same.
It takes an average of five large eggs to make one cup, but only four extra-large eggs. That means each extra-large egg averages 2 fluid ounces, or 1/4 cup. Large eggs average just 1.6 fluid ounces. On your breakfast plate that's not important, but when you bake, it can be a factor.
If you're making a recipe that calls for lots of eggs, such as pound cake or cream puffs, you can simply use four eggs instead of five for each cup of eggs the recipe calls for. Most recipes are less obliging, and call for only one or two eggs.
- Some baked goods -- typically quickbreads, coffee cakes, custards or biscuits -- are forgiving enough to accept the larger eggs without much effect. If anything, perhaps, you might use a little extra flour if a dough or batter is wetter than it should be. Delicate cakes, or cookies that rely on eggs for their texture, are more problematic.
- In a cake, you can compensate by reducing other liquids by a tablespoon per extra-large egg. One tablespoon is half a fluid ounce, just slightly more than the difference in size between the eggs.
- In cookies, where eggs often provide all the moisture, you might not have that option. Instead, beat the eggs first. Remove 1 tablespoon of the beaten egg, and then continue with your recipe.