Egg Yolk

What Is Egg Yolk?

Egg yolk is the yellow-orange part at the center of the egg, rich in fat and nutrients. Most of the egg's energy and many of its nutritional components are concentrated here; it is far fattier and more caloric than the white.

With its creamy, rich structure it gives sauces body and fullness; thanks to the natural emulsifiers it contains, it also binds fat and water together. This property makes it indispensable in mayonnaise, hollandaise sauce and many custards.

Nutritional Value of Egg Yolk

Egg yolk is high in calories, with about 322 kcal per 100 g; it is a food rich in fat (~27 g), protein and various vitamins and minerals. Its cholesterol content is high, so those watching their cholesterol are advised to consume it in moderation.

How Should Egg Yolk Be Consumed?

Since egg yolk is nutritious but rich in fat and cholesterol, it should be consumed in moderation as part of a balanced diet; as with any egg product there is a salmonella risk when eaten raw, so thorough cooking or using pasteurized product is safer.

This information is general; egg yolk is a food, not a substitute for medical treatment.

How Is Egg Yolk Separated and Selected?

The yolk of a fresh egg is firm, plump and does not break apart easily, which makes it easy to separate cleanly. A spread-out, watery yolk can be a sign of staleness; using fresh eggs matters both for flavor and usability.

• A fresh egg's yolk should be firm and plump
• A yolk that doesn't break apart easily is fresher
• A spread-out, watery yolk may be stale

How Is Egg Yolk Stored?

A separated egg yolk is kept in the fridge for a short time in a covered container (topped with a little water to keep it from drying out); since it dries out quickly, it should be used within a day or two. A whole egg keeps longer in the fridge in its shell.

Using Egg Yolk in the Kitchen

Egg yolk is used most in mayonnaise, hollandaise and cream (pastry cream), custard-like desserts, pasta sauces and glazing dough. Thanks to its emulsifying and thickening properties it binds sauces; it is brushed over dough for glazing.

Why Does Egg Yolk Bind Mayonnaise?

The natural emulsifiers in the yolk (such as lecithin) disperse and stabilize oil droplets in water, so the oil and water form a creamy emulsion (mayonnaise) without separating.

Frequently Asked Questions

Is egg yolk eaten raw?

It is not recommended due to the salmonella risk when consumed raw; in recipes containing raw yolk (such as homemade mayonnaise) it is safer to use pasteurized eggs.

Why is egg yolk separated from the white?

Some recipes want only the richness and body of the yolk (custard, sauce) or only the foam of the white (meringue); this is why eggs are separated into yolk and white for use.

Is egg yolk frozen?

Freezing the yolk on its own can cause it to gel; it is recommended to mix it with a pinch of salt or sugar before freezing. This way it stays usable once thawed.