How to Store Egg Yolks and Whites Separately

If you separate egg yolks and whites for storage, keep them in separate covered containers in the refrigerator. Yolks are more delicate than whites: their membranes are thinner, so exposure to air and bacteria can make them dry out and form a tough surface more quickly. How should egg whites be stored? Egg whites can be kept in a covered container in the refrigerator for 2–4 days. Their protein-rich structure means they keep longer than yolks and are less likely to dry out. If you have a large amount of egg whites, such as after making a recipe that uses only yolks, pour them into an ice cube tray in portions equivalent to one egg each and freeze them. Transfer the frozen cubes to a bag and label it to save space in the freezer. How should egg yolks be stored? Egg yolks can be kept in the refrigerator for no more than 1–2 days. Keep them in a container covered with enough water, or lightly salted water, to cover them; the water prevents direct air contact and slows the membrane from drying out. Without water, the surface can start to harden within a few hours. Changing the water every day can let the yolks keep for one additional day, but the total storage time should not exceed 2 days. Can both be frozen? Egg whites can be frozen without beating and retain their quality for 10–12 months. Beat egg yolks before freezing; otherwise, they become gelatinous and grainy after thawing. To prevent this, beat a small pinch of sugar into yolks for sweet recipes or a pinch of salt for savory recipes. What if a recipe uses only one part? Plan to use the leftover yolk or white soon so it does not go to waste. For example, leftover yolks from a cake recipe that uses only whites can be used in a custard or sauce during the same week. If you are storing the yolks, cover them with water as described above. When should they be discarded? Discard yolks that have turned gray, developed a crust, or have a sharp odor. Do not use whites that have become cloudy or pinkish. Check their appearance and smell; never taste a questionable piece of egg as a safety check. If in doubt, discard it. A few wasted eggs are far less important than cooking with a spoiled ingredient. Why does careful separation matter? A piece of shell or yolk mixed into the whites can make them harder to whip. Separate eggs with clean hands or an egg separator, and remove any shell fragments immediately. Separating eggs straight from the refrigerator can also be easier and cleaner because the yolk membrane is sturdier when cold than at room temperature; room-temperature eggs, however, are more suitable for whipping.