Adding eggs is one of the most interesting and crucial steps in a recipe. Eggs are an often over-looked, but critical ingredient in baking. Their primary function is to contribute to the structure of the baked item, but they also add flavor and color. Cakes, muffins and breads will not rise properly without the addition of fresh eggs. Many a recipe has failed because the wrong size or outdated eggs were used.
Egg Whites:
The egg white from a large egg is 90% water, 10% protein, weighs about 1 ounce and provides about 17 calories. It is the egg white protein that provides structure to baked goods. A good analogy would be a hot air balloon. Think of the egg white as being the balloon itself. The structure of the "egg balloon" traps the warm air, causing it to rise. In baked goods the egg protein "solidifies" from the oven heat, creating a structure to trap steam.
Egg Yolks:
The egg yolk from a large egg weighs only about 1/2 ounce. However, because it primarily consists of fat, cholesterol, vitamins and minerals, it provides about 60 calories. Egg yolks also contain a little protein and an amino acid called lecithin, a substance that makes sauces, like mayonnaise and Caesar salad dressing, thick and smooth. It is the yolk that contributes to the color and flavor of baked goods.
Egg Grades:
Eggs found in stores typically are labeled either as grade AA or grade A. These grades have no bearing on either size or freshness. In baking, you will see virtually no performance difference between the two grades.
Egg Color:
Eggs come in two colors - white and brown. The breed of the chicken determines the color of the egg shell. The nutritional value and quality of the egg is the same regardless of the color. Yolk color is the result of the diet of the chicken. Chickens fed grains that are yellow, such as cornmeal or alfalfa meal, will have medium yellow yolks. Those fed white cornmeal will have very light, almost colorless yolks. Marigold petals are added to chicken feed to produce golden or lemon-colored yolks.
Egg Size:
Egg sizes are jumbo, extra large, large, medium and small. The older the chicken, the larger the egg. The majority of recipes require large eggs. Use a large egg if the recipe doesn't indicate a specific size.
Size Equivalents:
Most recipes for baked goods call for large eggs. Although it is best to use a large egg, if you must substitute another size, using the following chart.
Number of Large
Eggs Required | Number of Eggs to Use Instead |
| Jumbo | X-Large | Medium | Small |
| 1 | 1 | 1 | 1 | 1 |
| 2 | 2 | 2 | 2 | 3 |
| 3 | 2 | 3 | 3 | 4 |
| 4 | 3 | 4 | 5 | 5 |
| 5 | 4 | 4 | 6 | 7 |
| 6 | 5 | 5 | 7 | 8 |
Life & Storage:
Eggs should be stored in the refrigerator and in the carton in which they came. Storing them in the egg trays found in refrigerators will significantly shorten their shelf life. It also is important to keep them refrigerated constantly. Even an hour spent on the kitchen counter can greatly reduce freshness.
Eggs should last about one month provided they are stored in their carton and in constant refrigeration. Egg whites out of the shell will keep in the refrigerator for about a week if they are tightly covered. Egg yolks out of their shell, on the other hand, will only last about 2 days if stored tightly covered.
Egg Safety:
Because of the possibility of salmonella contamination, only use eggs with shells that are unbroken and clean. It is unwise to eat homemade products containing raw eggs such as eggnog or raw cookie dough. If you are preparing a recipe that requires raw or lightly cooked eggs (i.e., homemade mayonnaise, eggnog, Caesar salad or dessert mousse) it would be best to substitute a pasteurized liquid eggs product which is available in most supermarkets.
