Separating eggs is a process, generally used in
cooking
Cooking, also known as cookery or professionally as the culinary arts, is the art, science and craft of using heat to make food more palatable, digestible, nutritious, or Food safety, safe. Cooking techniques and ingredients vary widely, from ...
, in which the
egg yolk
Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...
is removed from the
egg white
Egg white is the clear liquid (also called the albumen or the glair/glaire) contained within an egg. In chickens, it is formed from the layers of secretions of the anterior section of the hen's oviduct during the passage of the egg. It forms a ...
. This allows one part of the egg to be used without the other part, or each part to be treated in different ways. Recipes for
custard
Custard is a variety of culinary preparations based on sweetened milk, cheese, or cream cooked with Eggs as food, egg or egg yolk to thicken it, and sometimes also flour, corn starch, or gelatin. Depending on the recipe, custard may vary in con ...
call for egg yolks, for example.
The most common reason for separating eggs is so the whites can be
whipped. Also, because
cholesterol
Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils.
Cholesterol is biosynthesis, biosynthesized by all anima ...
is only found in the yolk, using only egg whites in a recipe will drastically reduce its cholesterol content.
Technique
All methods for separating eggs make use of the fact that the yolk can hold itself together, while the white is more runny. Since the yolks of older eggs are more watery, which makes separation difficult, it is best to begin with the
freshest eggs available.
Although many recipes require eggs to be at
room temperature
Room temperature, colloquially, denotes the range of air temperatures most people find comfortable indoors while dressed in typical clothing. Comfortable temperatures can be extended beyond this range depending on humidity, air circulation, and ...
, it is easiest to separate eggs that are cold. Eggs that are at room temperature can be separated, but this requires greater caution to avoid breaking the yolk. One solution is to separate the eggs, cover them, and then allow them to come to room temperature. In this method, eggs should not be allowed to sit too long because of the risk of bacteria growth. An alternative solution is to bring the bowl of egg whites (or yolks) up to temperature by placing it in another bowl of hot water.

Different methods:
* Break the egg and use your fingers to strain out the yolk, while the whites run into the bowl below.
* Crack the egg in half and cradle the yolk in one half of the shell (using the other half of the shell to keep it from slipping out) while draining the white into a bowl. If some white is left with the yolk, carefully pass the yolk back and forth between halves until it is all drained, being sure not to puncture the yolk on the sharp edges of the shell. Then deposit the yolk into another bowl. This method is discouraged by food safety experts due to the possibility of salmonella contamination.
* Use an egg separator, a device that can be set over a bowl, with a cup to catch the yolk and vents to allow the white to pass down.
* Break the egg into a
funnel
A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening.
Funnels are usually made of stainless steel, aluminium, glass, or plastic. The material used in its constructi ...
, capturing the yolk.
* Break the egg on to a plate, and trap the yolk under a glass. Carefully, drain off the whites, lifting the glass slightly.
* Use a needle to pierce the egg and run the whites out, leaving the yolk inside.
* Break the egg into a bowl and suck out the yolk with a plastic bottle.
References
Cooking techniques
Eggs (food)
Culinary terminology
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