Egg size matters, especially in cakes

Q. Does size matter ... in baking? If my pumpkin-pie recipe says large eggs, would extra-large or jumbo (which I usually have) be OK? And what about in a cake?

Jessie in San Mateo, Calif.

A. There is a way of using the eggs you usually have on hand and not ruining the recipe, but first a few basics that should be helpful.

Cakes are fragile creatures. In cakes if the recipe calls for four large eggs and you use four extra-large eggs the recipe will not work as well. This is because these recipes are chemical balancing acts of exacting ratios of fat to sugar, to flour, to eggs, to leavenings. In fact, in the French butter sponge cake called Genoise where you beat warm whole eggs with sugar and then fold in melted butter and flour, an extra-large egg instead of a large egg will give you a heavy cake.

In custard pies, which is what pumpkin pie actually is, you can fudge a bit. Extra-large instead of large in that pie will not change it radically.

The trick to using the eggs you have on hand is knowing how much each size egg weighs.

Since baking is all about balancing weights of ingredients, then if the recipe says four large eggs, you'll know what to do. Even if the recipe says only "egg" with no size indicated, it means "large."

Here are the equavalents:

1 large egg: 2 ounces

1 extra-large egg: 2.25 ounces

1 jumbo egg: 2.5 ounces

1 medium egg: 1.75 ounces

1 small egg: 1.5 ounces