Show notes

Types of eggs

The most common kinds of birds eggs for culinary uses; Quails eggs - These are very small and they can be quite expensive so they are a gourmet item. They look very attractive cut in half on a salad and make cute mini fried eggs as a treat for children. 5 quail's eggs = 1 hen's egg Duck and goose eggs - These are slightly larger than hen's eggs and more strongly flavored. They are also higher in cholesterol - particularly the goose egg so they should be used sparingly. Turkey eggs - These are much larger than a hen egg, about 1 ½ times the size, and are not very readily available. They have a similar taste to a hen's egg but they are also high in cholesterol. Ostrich eggs - These are very large - equivalent to around 20 hens eggs and can take about an hour to boil! Makes scrambled egg for a crowd.

Hens eggs
Hens eggs are the most commonly used in cooking and are usually brown or white. The color is determined by the breed of hen and both colors have the same nutritional value and cooking characteristics. The edible portion is about two thirds white and one third yolk. This will be the same in double yolked eggs, here the yolk material is divided into two units but the total yolk amount will be roughly the same as in a single yolk egg. The color of the yolk is determined by the type of feed.

Which size?
Hens eggs are graded by size - the sizing standards vary from country to country. Most recipes use large eggs unless stated otherwise, this will around 50- 55g/2oz of edible portion (i.e. excluding the shell) When halving a recipe which requires one egg, provided the whole egg is used, it can be broken into a cup, whisked with a fork to break up the yolk and then half measured out. 1 ½ tablespoons is approximately half a large egg.

Egg safety

Buying and storing
Buy the freshest possible, in some countries eggs are dated with the date of laying. They should keep for up to 4-5 weeks but for raw use only use very fresh eggs or pasteurized eggs. Check the shells for cracks, the shell is the egg's natural protection against infection so if there are cracks the egg may not be in optimum condition. If any eggs break on the way home use them up quickly. Store in the eggs in the original carton in the fridge prevents them picking up any odours through their shells and limits evaporation of liquid. Only store them at room temperature for a short period. Store them with pointed end down. Do not wash eggs as this will remove protective oils from the surface and the eggs will go off more quickly. (Egg producers wash them but then coat them with mineral oil to replace natural oils lost) If you are using eggs from free range/local producers which are unwashed then wash just before use to remove any dirt or feathers. This is important as dirt on the shell could fall into the food you are preparing. Take out of the fridge 1 hour before use to warm up to room temperature - particularly important for whisking egg whites but also for boiled eggs.

Using raw eggs
Eggs can be infected with Salmonella bacteria which can cause rather unpleasant food poisoning, at best some rather uncomfortable hours or days but at worst much more serious and raw eggs must be avoided by seniors, expectant mums and babies and young children. Some countries have pasteurized eggs available where the eggs have been held at a temperature high enough to sanitize them but low enough not to cook the egg. If these are available they are the safest option for recipes using raw eggs. If you really want to use raw, untreated eggs use the freshest possible from reliable sources, keep the dish chilled before serving and use it very quickly. There are no guarantees with this and so it best not to use raw unpasteurised eggs when catering for the at risk groups. In food that is thoroughly cooked there is no risk as any bacteria present will be destroyed and older eggs can be used.

Testing for freshness
Good stock rotation should ensure that you use your eggs in good condition and it is best not to buy in very large quantities so that you will replenish frequently with fresh eggs. It is impossible to tell the age of the egg by looking at it but there is a fun little test to do if you want to know if an egg is still usable. Dissolve 1 tbsp salt in 500ml (2 cups) water and stir to dissolve completely. Lower the egg into the water gently. If it lies on it side at the bottom of the water it is very fresh. If it lies with the blunt end slightly raised it is fresh and can be used in most recipes that require eggs. If it stands on end with the blunt end uppermost this is an old egg, if you still want to use it then hard boiling is the only suitable use. If it floats this egg is stale and should be discarded. This works because of the structure of the egg.

White and yolk are held inside the shell, between the shell and the edible part there are two thin membranes or skins. Moisture is able to pass from the egg white through these skins and out of the shell and so the edible part gets smaller and starts to shrink. Air is able to pass in through the shell and fills the space between the two membranes give a bubble of air, the older the egg the bigger the bubble and the more it floats. A larger air cell is not a problem but can give rather misshapen hard boiled eggs.

Using eggs
Eggs are very versatile and nutritious. They can be fried, boiled or poached. In baking they provide structure and strength and they are also used to thicken, emulsify (hold fat and water together), coat, bind, glaze and aerate or leaven. The white and the yolk have very different properties because of their composition. The white is mostly water and protein (88% & 10 %) whilst the yolk is more concentrated and contains fat (50% water, 17 % protein and 30% fat). The white is able to hold a lot of air and can be used for aerating, coagulates very quickly so it is good for binding and giving structure and strength. Yolks contain the lipoprotein; this means protein that is bound together with fat, this is really important for enriching mixtures, emulsifying fats and water and of course for color. It is this diversity in properties that make it very difficult to give a one fit all replacement for eggs when they must be avoided in the diet. You need to decide the major function of the egg in the recipe and then find another ingredient or ingredients to fill the role.

Basic egg techniques

Cracking an egg
This is a very basic but vital technique which may take a little practice to perfect. Hold the egg in one hand (right if right handed) and give a firm tap against a solid edge; cups, jugs and bowls are good and these should be glass, metal or porcelain - most plastic containers are not rigid enough for this. You want to get a good clean crack in the shell which is deep enough to get through to the white layer but not so deep to go all the way through to the yolk. Then insert ends of both thumbs into the indent and prise apart and carefully tip the egg into your container. You should have a whole yolk in a pool of white. It is good to practice your technique with recipes where you will mix the yolk and white together - scrambled eggs is a good starting point. It is also a good idea to crack the eggs into a cup or small bowl separate from the main mixture. In this way you can check for freshness, bad eggs have an unpleasant smell, and if you have a mishap and break the yolk when you need them separated or get some shell in the egg you will not spoil your mixture.

Separating eggs
There are gadgets available called egg separators, these are small cups that have a little hole or slit which allows the white to drain off whilst leaving yolk sitting in the cup. Some people use the egg shell halves and tip the yolk from one half to the other whilst allowing the white to drip into a bowl beneath, this works best if the two halves of the shell are of equal size and if the edges of the shell are not too ragged. But the easiest way is simply to use a saucer and an egg cup. Break the egg on to the saucer. Place the egg cup carefully over the yolk and hold firmly in place, tip the white into the bowl whilst holding the yolk in place with the cup. Tip the yolk into another bowl and repeat with other eggs if needed. If using separated eggs in a recipe you will get the best results with fresh eggs. Changes which occur in the egg during storage make the membrane or the skin around the egg more fragile so the older the egg the more likely the yolk is to break when you crack the egg open. This is worth remembering for fried or poached eggs also.

Storing extra whites or yolks
Extra whites or yolks can be stored for a short while in the refrigerator and used in other recipes. The egg white can just be stored in a covered container for two to three days. Egg yolks should be covered with fresh water before storage as the membrane or skin of the yolk tends to dry to hard crust. They can then also be stored covered for 1-2 days in the fridge. To use, carefully drain off the water leaving the yolks intact. They can also be frozen - whites can be frozen as they are - freeze in ones or twos for easy portioning later. Egg yolks need to be mixed with sugar or salt to lower the freezing point (to avoid structural damage by the ice crystals) Add a pinch of salt or sugar to each egg yolk and mix well. They should be labeled sweet or savory to avoid unpleasant surprises in later use.

 Whisking egg whites
When you are whisking egg whites you are incorporating air bubbles which are held in a foam by the proteins in the egg white. If there is even the smallest amount of fat this protein network cannot form correctly and you will not achieve the stiff foam that you need. The bowl should be completely grease free or it will interfere with protein. It is best to use a glass or metal bowl -copper is the best as that actually reacts with egg whites to give a more stable foam or stainless steel, and metal utensils. Plastic can absorb a bit of grease or fat and it is difficult get completely clean. Also even the smallest amount of egg yolk will prevent the whites whipping correctly. If it happens you will have to start again with a fresh egg and use the other egg for something else. Also it is important to use eggs at room temperature to get the best volume as cold eggs don't give as much volume. Take the eggs out of the refrigerator about an hour before you want to use them.

Listen to Eggs Part 2.