Nothing stimulates the practiced cook's imagination or the nutritionist's enthusiasm like a good fresh egg, for eggs contain all the balanced nutrients from which a complete organism develops.
Eggs can transform cake doughs by providing a structural framework for leavening, can thicken custards and make them smooth, can tenderize timbales and produce fine-grained ice creams. They bind gravies and mayonnaise, clarify or enrich soups, glaze rolls, insulate pie doughs against sogginess, create glorious meringues and souffles and make ideal luncheon and emergency fare.
Because fresh eggs do all these things better than old eggs and because there is no comparison in taste and texture between the two, always buy the very best quality you can find. It doesn't matter if their yolks are light or dark or if their shells are white or brown--as long as the shells are not shiny.
While there is no test, except tasting, for good flavor, the relative freshness of eggs may be determined by placing them in a bowl of cold water. Those that float are not usable. Unshelled onto a plate, a truly fresh egg has a yolk that domes up and stays up, and a thick and translucent white, containing a rope-like strand of material called chalaza which anchors the yolk in place. This is usable, as is the small dark fleck which indicates that the egg has been fertilized. Remove the fleck only if using the egg in a light-colored sauce or confection.
Strange as it may seem after stressing the purchase of fresh eggs, we now tack on an amendment. Do not use eggs fresher than three days old for hard-cooked eggs or for beating and baking. If you do, hard-cooked eggs will turn greenish and become difficult to peel, and cakes may fail to rise properly because the eggs will not beat to the proper volume.
Never use a doubtful egg with any odor or discoloration, especially one that is cracked: here is where salmonella can develop.
Eggs should really be bought and measured by weight, but tradition is against this sensible approach. We assume that you are using 2-ounce eggs. These are known in the trade as Large. They should carry a Grade A stamp as well as the date of grading. If in doubt about size, weigh or measure them. The yolk of a 2-ounce egg is just about 1 tablespoon plus a teaspoon; the white, about 2 tablespoons. To realize how great a difference egg size has on volume, two large eggs give you about half a cup, but it takes three medium eggs to fill that same half-cup. When you decrease a recipe and want to use only part of an egg, beat the egg slightly and measure about 1 1/2 tablespoons for half an egg and about 1 tablespoon for one-third.
Don't expect the same texture or flavor from eggs of other fowl--from lark to ostrich; one of the latter, by the way, will serve 24 for brunch. In using offbeat eggs be very sure of freshness.
When fresh eggs are not available, dried eggs are a convenience, but they are not an economy. Because of bacterial dangers, they must always be used in recipes that call for thorough cooking, unless a large percentage of acid is indicated. Packaged dried eggs should be stored at 70 degrees and, if opened, should be refrigerated in a tightly lidded glass container.
To reconstitute the equivalent of three fresh eggs, sift 1/2 cup dried whole egg powder over 1/2 cup water. Whip until smooth. To substitute for 1 egg, use 2 1/2 tablespoons sifted dry egg powder to 2 1/2 tablespoons water. Beat until smooth. Use either of these mixtures within five minutes after combining. You may prefer to add the egg powder to the dry ingredients, and the water to the rest of the liquid called for in the recipe.