TIP: Egg Whites

• Tightly covered egg whites can be refrigerated for up to 4 days, frozen for up to 6 months.
• An easy way to freeze extra egg whites is to place one in each section of an ice-cube tray. Freeze, then pop the egg-white cubes out into a freezer weight plastic bag. Thaw what you need overnight in the refrigerator.
• Eggs separate more easily when they are cold, but you'll get more volume when beating egg whites if you wait until they are room temperature.
• To safely separate eggs, crack one at a time, placing each white in a custard cup before transferring it to the mixing bowl. This prevents accidentally getting any broken yolk into a bowl of whites. A drop of egg yolk, which contains fat, will prevent egg whites from reaching their full volume.
• If a speck or two of yolk gets into the whites, use the corner tip of a paper towel to blot it up. A cotton-tipped swab works well, too.
• To quickly warm cold egg whites for eating, set the bowl of whites in a larger bowl of warm water. Stir occasionally until whites have reached room temperature.
• For beating egg whites until stiff, use a small, deep bowl with a rounded bottom for 4 to 5 egg whites; a large, deep bowl for more.
• The composition of the bowl in which you beat egg whites can make a big difference. Copper bowls react chemically with egg whites to form fluffy, high-rise whites. The same result can be obtained using stainless steel or glass bowls with the addition of cream of tartar. The naturally slick surface of a glass bowl does not give as much traction for the egg whites to climb the sides. Never use aluminum (which can cause egg whites to turn slightly gray) or plastic or wooden bowls, which are hard to clean well enough to be fat-free.
• Adding a small amount of acid, such as cream of tartar, lemon juice or vinegar, stabilizes egg whites and allows them to reach their full volume and stiffness. The natural acid on the surface of a copper bowl achieves the same result. Use 1/8 teaspoon of the acid ingredient per egg white, except for meringues, where 1/8 teaspoon is sufficient for 2 egg whites. Add the acid to the whites just as they begin to become frothy during beating.
• When beating whites with an electric mixer, start at medium-low speed and gradually increase to high.
• Egg whites beaten without sugar will not peak as firmly as those with sugar.
• It's very important to beat egg whites only until they are stiff, but not dry. Over beaten egg whites will collapse and begin to reliquify.
• If you accidentally over beat egg whites, gently stir in another egg white that's been beaten by hand just until frothy. Once the mixture is combined and the whites are again shiny and moist, remove about 1/4 cup to bring the volume back into balance.
• To prevent loss of volume, use egg whites as soon as they are beaten.
• Folding stiffly beaten egg whites into another mixture must be done by hand. Using a large rubber spatula, quickly but gently cut into the middle of the mixture. Bring the bottom of the batter up and over the remaining mixture. Rotate the bowl a quarter turn with each folding motion. Fold gently to retain as much air as possible. Stop folding when no white streaks remain.
• If folding stiffly beaten egg whites into a very thick or heavy mixture, first stir in about a quarter of the whites. This will loosen the mixture and enable the remainder of the beaten whites to be folded in with ease.