What are eggs?

The ultimate convenience food, eggs are powerhouses of nutrition packed with protein and a range of 18 vitamins and minerals. They're also hugely versatile. Almost all eggs are edible but the most commonly consumed are hen's eggs. Bantam, quail, duck and goose eggs are also readily available and vary in size and flavour.

Eggs bind mixtures together as well as enriching the flavour. Beaten egg whites provide volume by trapping air.

Read our guide on the health benefits of eggs.

How to prepare eggs

Just crack them open, and you're ready to go: tap the middle of the egg against the rim of a bowl to crack the shell, insert the tips of your thumbs into the crack, draw the two halves apart to drop the egg into the bowl and use one half of the shell to fish out any fragments of shell that may have fallen into the bowl.

It's a good idea to crack each egg into an empty bowl before adding it to your mixing bowl, just in case it's bad. If you're in any doubt about how fresh an egg is before you crack it open, drop it in a glass of water. A fresh egg will drop to the bottom of the glass and stay there. A slightly older (but still safe to eat) egg will hover in the middle, while a stale egg will float on the surface – a sure sign that it should be thrown away. Once open, a very fresh egg will have a plump yolk that stands proud from the white, and the white itself will have two layers, the one that surrounds the yolk being the higher of the two.

Watch our video on how to achieve perfect poached eggs:

How to cook eggs

Cook eggs on their own, either scrambled, poached, boiled or fried, or use them to make dishes such as omelettes, frittatas, soufflés, pancakes, sauces or cakes, or to glaze breads and pies.

When baking, use eggs at room temperature to avoid your mixture from curdling. Beat them first before adding them to the mixture.

Read more about the health benefits of eggs.

How to store eggs

To maintain freshness, it's better to store eggs in the fridge as they will last longer. Whole eggs will last for around three weeks after laying if kept in the fridge in their box or in a separate covered compartment. You can store whites for up to three weeks in a container and cover. Yolks will last up to three days, and should also be covered and chilled. Both whites and yolks can be frozen (separately) for up to three months.

Keep eggs away from strong-smelling foods as they can become tainted.

Fresher eggs work best for boiling, poaching or frying, while older eggs can be used in baking, glazing and for whipping up the whites into meringues.

How to buy eggs

Hen's eggs come in different grades (Grade A or Class A are the best) and sizes, which are defined by weight, rather than volume (S, 45g; M, 53g; L, 63g; XL, 73g). For individual servings, such as when frying or poaching, size doesn't matter so much. But baking is different – if you can't find the size the recipe calls for, make sure you're using the right volume.

Always select eggs marked with the farthest away 'best before' date (28 days after they have been laid) and eat them before it expires. Never buy eggs that are broken or cracked. The colour of the shell isn't an indication of quality or the bird's feed, it's dictated by the breed of bird.

The way in which the bird that laid the egg is reared is also an important factor in making your selection. Organic eggs are most expensive, as they are laid by hens who have been reared in the most humane way possible, with strict criteria to govern their housing, freedom of movement, feed (all-organic) and environment (organic land). Free-range is next, then barn eggs. Caged hen's eggs are the cheapest, as the hens who lay them are farmed in the cheapest manner with very limited room to move around, high densities and no access to direct sunlight.

Another label to look out for is the Lion Quality stamp – eggs marked with this will have been laid by hens vaccinated against salmonella.

Read more about standards in egg production at British Egg Information, the official site for British Lion Quality eggs.