Prices do vary, depending on the time of year and market conditions, but eggs are relatively low in cost, making them an economical source of high quality protein in the diet. Eggs are used for a variety of purposes in cooking and baking, such as to emulsify, glaze, leaven, bind, and thicken. Eggs are graded for quality on thickness of white, firmness of yolk, and size of interior air pocket. However, lower grades are slightly less expensive and will work just fine in cakes and cookies, for scrambled eggs, or for any other preparations where thickness of the white and strength of the yolk aren t as critical. The size of the egg is not related to the quality.
Size simply represents the amount of egg available from a dozen eggs.
Placing an egg in a bowl of cold water can test for freshness. A fresh egg will remain on the bottom. Discard any egg that rises to the surface of the water. Egg substitutes may be used in place of whole eggs in cooking to reduce fat and cholesterol. Commonly available in supermarkets and restaurants, egg substitutes were developed by the food industry in response to public concern with cholesterol in eggs.