Powdered eggs are fully dehydrated eggs. They are made in a spray dryer

Spray drying

Spray drying is a method of producing a dry powder from a liquid or slurry by rapidly drying with a hot gas. This is the preferred method of drying of many thermally-sensitive materials such as foods and pharmaceuticals. A consistent particle size distribution is a reason for spray drying some...

 in the same way that powdered milk

Powdered milk

Powdered milk is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and does not need to be refrigerated, due to its low moisture content. Another purpose is to reduce its bulk for...

 is made. The major advantages of powdered eggs over fresh eggs are the price, reduced weight per volume of whole egg equivalent, and the shelf life

Shelf life

Shelf life is the length of time that food, drink, medicine, chemicals, and many other perishable items are given before they are considered unsuitable for sale, use, or consumption...

 (which, when properly sealed, can be 5 to 10 years). Other advantages include smaller usage of storage space, and lack of need for refrigeration

Refrigeration

Refrigeration is a process in which work is done to move heat from one location to another. This work is traditionally done by mechanical work, but can also be done by magnetism, laser or other means...

. Powdered eggs can be used without rehydration when baking

Baking

Baking is the technique of prolonged cooking of food by dry heat acting by convection, and not by radiation, normally in an oven, but also in hot ashes, or on hot stones. It is primarily used for the preparation of bread, cakes, pastries and pies, tarts, quiches, cookies and crackers. Such items...

, and can be rehydrated to make dishes such as scrambled eggs

Scrambled eggs

Scrambled eggs is a dish made from beaten whites and yolks of eggs . Beaten eggs are put into a hot pot or pan and stirred frequently, forming curds as they coagulate.-Sample preparation:...

 and omelette

Omelette

In cuisine, an omelette or omelet is a dish made from beaten eggs quickly cooked with butter or oil in a frying pan, sometimes folded around a filling such as cheese, vegetables, meat , or some combination of the above...

s.

Powdered eggs were a staple of camp cooking at least as early as 1912.

Powdered eggs were used throughout the Second World War for rationing and were widely used during wartime shortages. Powdered Eggs are also known as Dried Eggs.

The modern method of manufacturing powdered eggs was developed in the 1930s by Albert Grant and co of the Mile end Road. This cake manufacturer was importing liquid egg from China and one of his staff realised that this was 95% water. An experimental freeze drying plant was built and tried. Then a factory was set up in Singapore to process Chinese egg. As war approached Grant transferred his dried egg facility to Argentina. The patent was lifted by the British government during the war and many other suppliers came into the market notably in the USA.